Methods and devices for delivering and affixing tissue scaffolds

ABSTRACT

Methods and devices are provided for delivering and affixing tissue replacements. In one embodiment, a tissue scaffold can be delivered into a patient through a cannula to a cavity formed at a defect site in tissue, e.g., cartilage. A delivery shaft can be used to deliver the scaffold through the cannula, and a loading device can help load the scaffold onto the delivery shaft. A delivery guide device can position and temporarily hold the scaffold within the cavity. The delivery guide device can guide one or more surgical instruments to the scaffold to affix the scaffold within the cavity, e.g., to bone underlying the scaffold, using at least one securing mechanism.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.12/412,499 (now U.S. Pat. No. 8,241,298, filed on Mar. 27, 2009, andentitled “Methods and Devices for Delivering and Affixing TissueScaffolds,” which is incorporated herein by reference in its entirety.

FIELD OF THE INVENTION

The present invention relates to methods and devices for delivering andaffixing tissue scaffolds.

BACKGROUND OF THE INVENTION

Injuries to soft tissue, such as cartilage, skin, muscle, bone, tendon,and ligament, frequently require surgical intervention to repair thedamage and facilitate healing. Such surgical repairs can includesuturing or otherwise repairing the damaged tissue with known medicaldevices, augmenting the damaged tissue with other tissue, using animplant, a graft, or any combination of these techniques.

One common tissue injury involves damage to cartilage, which is anon-vascular, resilient, flexible connective tissue. Cartilage typicallyacts as a “shock-absorber” at articulating joints, but some types ofcartilage provide support to tubular structures, such as for example,the larynx, air passages, and the ears. In general, cartilage tissue iscomprised of cartilage cells, known as chondrocytes, located in anextracellular matrix, which contains collagen, a structural scaffold,and aggrecan, a space-filling proteoglycan. Several types of cartilagecan be found in the body, including hyaline cartilage, fibrocartilage,and elastic cartilage. Hyaline cartilage can appear in the body asdistinct pieces, or alternatively, this type of cartilage can be foundfused to the articular ends of bones. Hyaline cartilage is generallyfound in the body as articular cartilage, costal cartilage, andtemporary cartilage (i.e., cartilage that is ultimately converted tobone through the process of ossification). Fibrocartilage is atransitional tissue that is typically located between tendon and bone,bone and bone, and/or hyaline cartilage and hyaline cartilage. Elasticcartilage, which contains elastic fibers distributed throughout theextracellular matrix, is typically found in the epiglottis, the ears,and the nose.

One common example of hyaline cartilage injury is a focal articularcartilage defect in the knee. A strong impact to the joint can result inthe partial removal of a cartilage fragment of various size and shape orsufficiently damage the extracellular matrix of the cartilage to causedegeneration of cartilage. If left untreated, damaged articularcartilage can restrict joint function, cause debilitating pain and mayresult in long term chronic diseases such as osteoarthritis, a diseasecharacterized by cartilage breakdown and unfavorable changes in theunderlying bone. As injuries to the articular cartilage tissue generallydo not heal on their own, surgical intervention is often necessary torepair symptomatic lesions. The current modality of treatment consistsof lavage, removal of partially or completely unattached tissuefragments. In addition, the surgeon will often use a variety of methodssuch as abrasion, drilling, or microfractures, to induce bleeding intothe cartilage defect and formation of a clot. It is believed that thecells coming from the marrow will form a scar-like tissue that isfibrocartilaginous in nature and can only provide temporary relief tosome symptoms. Unfortunately, the repair tissue does not have the samemechanical properties as hyaline cartilage and therefore degrades fasterover time as a consequence of wear. Patients typically require asecondary procedure to alleviate symptoms.

More recently, experimental approaches involving the implantation ofautologous chondrocytes have been used with increasing frequency. Thechondrocytes are obtained by harvesting a piece of cartilage from apatient using a biopsy and then cells are extracted from the tissuesample and cultured to the appropriate numbers in the laboratory. Theexpanded chondrocytes are then provided to the surgeon in the form of acell suspension or pre-loaded onto a synthetic or natural biodegradable,biocompatible scaffold for placement into the cartilage defect site.Sometimes, these living cells are placed in a three-dimensional naturalor synthetic scaffold or matrix, and are kept under tissue specificculture conditions to create a transplantable function tissuereplacement. If provided with the appropriate conditions and signals,the cells will proliferate, differentiate, and secrete various matrixmolecules to create an actual living tissue that can be used as areplacement tissue to be implanted back into the defect site in thepatient.

Other techniques for repairing damaged cartilage employ cells other thanchondrocytes to produce the desired hyaline-like tissue. Stem orprogenitor cells, such as the cells within fatty tissue, muscle, or bonemarrow, have the potential to regenerate bone and/or cartilage in apatient. Stem cells can be from that patient, i.e., autogeneic, or fromanother patient, i.e., allogeneic. These progenitor cells in addition toother cells, such as cells from the synovium, are thought to regeneratecartilage tissue when placed in an environment favorable for inducingcartilage formation.

Other surgical techniques for the surgical treatment of damaged tissueinclude the use of surgical implants, scaffolds, or matrices. Varioussurgical implants have been used in surgical procedures to helpregenerate cartilage without the use of cells. For example, implants canbe created consisting of porous biodegradable, biocompatible polymericmatrices. Other examples include matrices derived from biopolymers suchas hyaluronic acid, collagen, and fibrin. These implants are often usedin conjunction with marrow stimulation techniques, such asmicrofracture, such that the marrow can provide the cells as well asother stimulants that will help to regenerate cartilage.

Before an implant can be placed into the patient, preparations must bemade to both the defect site and the implant to ensure good integrationof the implant with the cartilage surrounding the defect. The patientmust be prepared by clearing the degenerate or damaged tissue from thedefect site. Particularly in arthroscopic procedures where access to thesurgical site is limited, clearing space at the defect site can bedifficult and time consuming in attempts to minimize any trauma to theneighboring healthy cartilage and/or subchondral bone, i.e., the boneunderlying the defect. The implant must also be prepared by sizing itfrom its laboratory-created size to match the cleared defect space inthe patient. Because the implant cannot be appropriately sized until thespace at the defect site in the patient has been formed and its size canbe identified, the implant has to be prepared for implantation ad hocduring the surgical procedure. Errors in sizing the implant during thestress of surgery can prolong the surgical procedure and can result inrepeated resizing of the tissue replacement to an acceptable size. Insome cases attempts to size the implant can result in no appropriatelysized implant if it has been cut to one or more unusable sizes. Anunusable implant can necessitate creation of another implant in anotherexpensive, time-consuming, and medically intrusive process followed byanother attempt at implantation in the patient.

Accordingly, there remains a need for methods and devices for placing animplant into the patient.

SUMMARY OF THE INVENTION

The present invention generally provides methods and devices fordelivering and affixing tissue scaffolds. In one embodiment, a tissuescaffold loading system is provided that includes a delivery shafthaving at least one prong that extends from a distal end thereof andthat is configured to extend through a tissue scaffold. The tissuescaffold loading system also includes a loading block having a surfaceconfigured to seat a tissue scaffold thereon, the surface having atleast one opening formed therein and configured to receive the at leastone prong on the delivery shaft such that the at least one prong canextend through a tissue scaffold seated on the surface. The loadingblock further includes a guide member extending from the surface andhaving at least one channel formed therein that is positioned to guidethe at least one prong into the at least one opening on the surface.

The tissue scaffold loading system can have any number of variations.For example, the at least one prong can include two prongs, the at leastone opening can include two openings, and the at least one channel caninclude two channels. The at least one opening formed in the surface ofthe loading block can be in the form of an elongate slot configured toallow the at least one prong on the elongate shaft to slide therein. Foranother example, the at least one opening can be located a predetermineddistance from a terminal edge of the surface such that the at least oneprong will extend through a predetermined location on a tissue scaffoldseated on the surface and having perimeter abutting the terminal edge.In some embodiments, the guide member can have a first portion extendingsubstantially perpendicular to the surface and a second portionextending substantially parallel to the surface, the at least onechannel being formed in the second portion. The tissue scaffold loadingsystem can include a tissue scaffold having a plurality of pores, eachof the pores having a diameter substantially equal to a diameter of theat least one prong.

In some embodiments, the tissue scaffold loading system can include adelivery cannula having an inner lumen extending therethrough andconfigured to receive the delivery shaft therein. A funnel can beremovably mated to a distal end of the delivery cannula. The deliveryshaft can be configured to be inserted into a distal end of the deliverycannula, and the delivery cannula can include a stop configured to limitproximal movement of the delivery shaft within the delivery cannula toposition the at least one prong at a predetermined location within thedistal end of the delivery cannula. The tissue scaffold loading systemcan also include a delivery guide slidably disposable over the deliveryshaft and having a distal end configured to engage a tissue scaffolddisposed on the at least one prong on the distal end of the deliveryshaft and to hold the tissue scaffold against a surface of bone.

In another embodiment, a tissue scaffold delivery system is providedthat includes a delivery guide having an inner lumen extendingtherethrough and at least one tooth extending from a perimeter of adistal end thereof. The at least one tooth is configured to penetrate atissue scaffold and to engage bone to hold a tissue scaffold in a fixedposition relative to the bone. The delivery guide also includes at leastone window adjacent to the distal end that is configured to enableviewing of a component disposed within the inner lumen at the distalend.

The tissue scaffold delivery system can have a variety of modifications.For example, the at least one window can include a plurality of cut-outsformed in the delivery guide and/or a transparent portion formed in thedelivery guide. In some embodiments, the delivery guide can include analignment mechanism configured to position a tool inserted therethroughin a predetermined radial position relative to the delivery guide. Thetissue scaffold delivery system can include a punch tool configured tobe advanced through the inner lumen of the delivery guide and to preparebone for attachment of a tissue scaffold thereto. The bone preparationtool can include a punch tool that has at least one prong configured topunch at least one hole through a tissue scaffold held by the at leastone prong and into bone underlying the tissue scaffold. For anotherexample, the tissue scaffold delivery system can include a scaffoldseating tool configured to be advanced through the inner lumen of thedelivery guide. The scaffold seating tool can include afastener-applying tool having a fastener-retaining member on a distalend thereof and can be configured to retain at least one fastener and toapply the fastener through a tissue scaffold held in position by the atleast one tooth to fasten the tissue scaffold to a bone underlying thetissue scaffold. For yet another example, the tissue scaffold deliverysystem can include a delivery shaft having at least one prong extendingfrom a distal end thereof. The at least one prong can be configured toextend through a tissue scaffold, and the delivery guide can bedisposable over the delivery shaft such that the at least one tooth isconfigured to engage a tissue scaffold disposed on the at least oneprong of the delivery shaft. In some embodiments, the tissue scaffolddelivery system can include a delivery cannula having a funnel coupledto a distal end thereof, the delivery shaft being slidably disposablethrough the delivery cannula.

In another aspect, a method for loading a tissue scaffold onto adelivery shaft is provided that includes positioning a tissue scaffoldon a surface of a loading block such that the tissue scaffold isdisposed over at least one opening formed in the surface, and advancingat least one prong extending from a distal end of a delivery shaft alongat least one channel formed in a guide member on the loading block. Theat least one channel guides the at least one prong through the tissuescaffold and into the at least one opening.

The method can have any number of variations. For example, the guidemember can guide the at least one prong through the tissue scaffold at apredetermined location relative to a perimeter of the tissue scaffold.For another example, the at least one opening can include at least oneelongate slot, and the method can further include sliding the at leastone prong through the at least one slot and removing the at least oneprong from the at least one slot with the tissue scaffold attachedthereto. In some embodiments, positioning a tissue scaffold on a surfaceof a loading block can include abutting a perimeter of the tissuescaffold against a surface of the guide member and/or positioning atleast a portion of the tissue scaffold underneath at least a portion ofthe guide member. A surface of the tissue scaffold having viable tissuecells disposed thereon can be positioned in contact with the surface ofthe loading block.

In another aspect, a method for delivering a tissue scaffold is providedthat includes advancing a proximal end of a delivery shaft into a distalend of a delivery cannula to position a tissue scaffold disposed on adistal end of the delivery shaft within the distal end of the deliverycannula. The delivery cannula causes the tissue scaffold to fold aroundat least one prong on the distal end of the delivery shaft as the tissuescaffold is advanced into the distal end of the delivery cannula.

The method can have any number of variations. For example, the tissuescaffold can include viable tissue cells disposed on a first surfacethereof. The first surface can be prevented from coming into contactwith an inner surface of the delivery cannula when the tissue scaffoldis folded to thereby protect the viable tissue cells. For anotherexample, the delivery cannula can include a funnel on the distal endthereof that folds the tissue scaffold. For yet another example, themethod can include advancing the cannula into a body of a patient withthe tissue scaffold and delivery shaft disposed therein, and positioningthe at least one prong on the delivery shaft against bone to positionthe tissue scaffold. In some embodiments, the method can also includeremoving the cannula leaving the delivery shaft and tissue scaffoldextending into a body of a patient, and advancing a delivery guide overthe delivery shaft to cause a distal end of the delivery guide to engagethe tissue scaffold and engage the bone, thereby holding the tissuescaffold in a fixed position against the surface of the bone. The methodcan further include removing the delivery shaft leaving the deliveryguide extending into a body of a patient and holding the tissue scaffoldagainst the surface of bone, and advancing a punch tool through thedelivery guide, through the tissue scaffold, and into the bone to format least one hole in the bone. The punch tool can optionally be viewedthrough at least one window formed in the delivery guide adjacent to thedistal end of the delivery guide. The delivery guide can have analignment mechanism that aligns the punch tool at a predetermined radialorientation relative to the delivery guide. The method can also includeremoving the punch tool from the delivery guide and inserting afastener-applying tool through the delivery guide to insert at least onefastener through the tissue scaffold and into the at least one holeformed in the bone by the punch tool. The delivery guide can have analignment mechanism that aligns the fastener-applying tool at apredetermined radial orientation relative to the delivery guide.

In another embodiment, a method for delivering a tissue scaffold isprovided that includes positioning a distal end of a delivery guide on atissue scaffold and against a surface of bone to hold a tissue scaffoldat a fixed position relative to the surface of the bone, and advancing afastener-applying tool through the delivery guide to insert a fastenerthrough the tissue scaffold and into the bone, thereby fastening thetissue scaffold to the bone at the fixed position.

The method can vary in any number of ways. For example, positioning adistal end of the delivery guide can include penetrating at least onetooth on the delivery guide through the tissue scaffold and into thebone. For another example, the method can include, prior to advancing afastener-applying tool through the delivery guide, advancing a punchtool through the delivery guide to form at least one hole through thetissue scaffold and into the bone for receiving the at least onefastener. In some embodiments, an alignment feature on the deliveryguide can align the fastener-applying tool at a predetermined radialorientation relative to the delivery guide. For still another example,the method can include, prior to positioning a distal end of a deliveryguide, positioning the tissue scaffold against the surface of bone usinga delivery shaft. The delivery guide can be advanced over the deliveryshaft to position the distal end of the delivery guide on the tissuescaffold and against the surface of the bone.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be more fully understood from the following detaileddescription taken in conjunction with the accompanying drawings, inwhich:

FIG. 1 is a partial perspective view of one embodiment of a deliverysystem that includes a delivery shaft having a tissue scaffold attachedthereto being proximally advanced into a cannula having a funnel at adistal end thereof;

FIG. 2A is an exploded perspective view of the delivery shaft of FIG. 1;

FIG. 2B is a cross-sectional view of one embodiment of a lockingmechanism formed in the delivery shaft of FIG. 2A;

FIG. 3 is a perspective view of one embodiment of a loading block;

FIG. 4 is a side view of the loading block of FIG. 3;

FIG. 5 is a top view of the loading block of FIG. 3;

FIG. 6 is a top view of a cross-section of a main body of the loadingblock of FIG. 4;

FIG. 7 is an enlarged top view of the loading block of FIG. 5;

FIG. 8 is a partial perspective view of the tissue scaffold of FIG. 1 ona surface of the loading block of FIG. 3 and the delivery shaft of FIG.2A using the loading block to advance prongs at a distal end of thedelivery shaft through the tissue scaffold;

FIG. 9 is a partial side view of the tissue scaffold of FIG. 8 attachedto the prongs of the delivery shaft;

FIG. 10 is a side view of the cannula of FIG. 1;

FIG. 11 is an exploded perspective view of the cannula of FIG. 10;

FIG. 12 is a cross-sectional side view of the funnel of the cannula ofFIG. 1;

FIG. 13 is a distal end view of the funnel of FIG. 12;

FIG. 14 is a partially transparent perspective view of the scaffold ofFIG. 1 attached to the prongs of the delivery shaft and disposed in thecannula in a folded configuration;

FIG. 15 is a partial cross-sectional perspective view of the cannula ofFIG. 1 being advanced through tissue toward a cavity formed at a tissuedefect site in a patient;

FIG. 16 is a partial cross-sectional perspective view of the deliveryshaft of FIG. 1 being distally advanced through the cannula of FIG. 15showing and the tissue scaffold advancing from the distal end of thecannula;

FIG. 17 is a partial cross-sectional perspective view of the cannula ofFIG. 16 being removed from around the delivery shaft and from inside thepatient;

FIG. 18 is a side view of one embodiment of a delivery guide;

FIG. 19 is an enlarged side view of a distal end of the delivery guideof FIG. 18;

FIG. 20 is a cross-sectional view of the distal end of the deliveryguide of FIG. 18;

FIG. 21 is a cross-sectional view of the distal end of the deliveryguide of FIG. 18;

FIG. 22 is another side view of the delivery guide of FIG. 18;

FIG. 23 is an enlarged side view of a distal end of the delivery guideof FIG. 22;

FIG. 24 is a perspective view of a distal end of another embodiment of adelivery guide having a transparent distal portion and having aremovable distal ring with at least one bone-engaging element extendingtherefrom;

FIG. 25 is a perspective view of a proximal end of another embodiment ofa delivery guide having an alignment mechanism;

FIG. 26 is a partial cross-sectional perspective view of the deliveryguide of FIG. 18 being advanced over the delivery shaft of FIG. 17 andtoward the tissue scaffold attached to the delivery shaft;

FIG. 27 is a partial cross-sectional perspective view of the deliveryguide of FIG. 26 advanced over the delivery shaft and holding the tissuescaffold in a fixed position in a cavity at the tissue defect site;

FIG. 28 is a side view of one embodiment of a punch tool;

FIG. 29 is a partial cross-sectional perspective view of the punch toolof FIG. 28 disposed in the delivery guide of FIG. 27, with the deliveryshaft removed from the delivery guide, and a hammer hitting a proximalend of the punch tool to punch one or more holes in the tissue scaffoldin the cavity and in bone underlying the tissue scaffold;

FIG. 30 is a partial cross-sectional perspective view of afastener-applying tool disposed in the delivery guide of FIG. 29, withthe punch tool removed from the delivery guide, and applying one or morefasteners through the holes formed by the punch tool; and

FIG. 31 is a perspective view of the tissue scaffold of FIG. 30 attachedto patient with a fastener.

DETAILED DESCRIPTION OF THE INVENTION

Certain exemplary embodiments will now be described to provide anoverall understanding of the principles of the structure, function,manufacture, and use of the devices and methods disclosed herein. One ormore examples of these embodiments are illustrated in the accompanyingdrawings. Those skilled in the art will understand that the devices andmethods specifically described herein and illustrated in theaccompanying drawings are non-limiting exemplary embodiments and thatthe scope of the present invention is defined solely by the claims. Thefeatures illustrated or described in connection with one exemplaryembodiment may be combined with the features of other embodiments. Suchmodifications and variations are intended to be included within thescope of the present invention.

The present invention generally provides various methods and devices fordelivering and affixing implants. In general, various tools andtechniques are disclosed for delivering a tissue scaffold to a cavityformed at a defect site in tissue, e.g., cartilage. In one embodiment, adelivery shaft is provided for engaging a scaffold and delivering thescaffold arthroscopically to a defect site in tissue. A loading block isprovided and can be used to facilitate loading of the scaffold onto thedelivery shaft, and a cannula is provided for containing and protectingthe scaffold during delivery. Once the scaffold is delivered to a defectsite, various additional devices can be used to affix the scaffoldwithin a cavity formed in the tissue at the defect site. For example, inone embodiment a delivery guide is provided for holding the scaffoldwithin the cavity, for example during removal of the delivery shaft andduring attachment of the tissue scaffold to bone. A punch tool is alsoprovided for forming one or more holes in bone through the scaffold, anda fastener-applying tool is provided for delivering a fastener to thescaffold to attach the scaffold to bone. The punch and fastener-applyingtools can be configured to be inserted through the delivery guide. Thepresent invention thus provided a variety of tools that can be usedtogether in various combinations to aid in delivery and attachment of atissue scaffold to a cavity formed at a defect site in tissue.

A person skilled in the art will appreciate that the term “tissue” asused herein is intended to encompass a variety of materials, e.g.,cartilage, organs, and any other material that can be repaired using atissue scaffold, and that the term “cartilage” as used herein can referto any type of cartilage, e.g., hyaline cartilage, fibrocartilage, andelastic cartilage. A person skilled in the art will also appreciate thatthe term “defect site” as used herein is intended to encompass a currentor former location of tissue that is damaged, unhealthy, or is otherwiseundesirable and intended for repair with an implant. A person skilled inthe art will also appreciate that the term “tissue replacement,”“implant,” “scaffold,” or “matrix” as used herein is intended toencompass any surgically safe implant that is configured to be implantedin a patient to allow for tissue repair and regrowth.

A person skilled in the art will also appreciate that while the methodsand devices are described in connection with minimally invasivearthroscopic procedures in which surgical devices are introducedpercutaneously into a body cavity through a small opening formed in apatient, the methods and devices disclosed herein can be used innumerous surgical procedures and with numerous surgical instruments,including mini-open and open surgical procedures. A person skilled inthe art will also appreciate that while the methods and devices aredescribed in connection with chondral cartilage repair, the methods anddevices can be used in other tissue repairs related to the knee, e.g.,cartilage at the patella, or to other articulating surfaces, e.g.,shoulder, ankle, hip, and elbow, and in any other type of tissue repairusing a tissue replacement implant.

In an exemplary embodiment, a patient having a cartilage lesion at adefect site at the articular surface of a bone joint, such as thefemoral condyle at the knee, can be prepared for tissue repair surgery.Through an arthrotomy incision, the knee joint can be opened and thedefect site exposed. The size and shape of the lesion can vary, althougha lesion at the femoral condyle traditionally has an elliptical shapehaving a surface area of about 3 cm² (300 mm²). The undesirablecartilage tissue, which can include fibrillations and fissures, can beremoved, to form a cavity in the tissue. An amount of healthy cartilageadjacent the lesion can also be removed in the process of removing thelesion. Debridement of the articular surface can be deep enough toexpose a calcified layer of cartilage and/or a subchondral bone surface,e.g., in a range of about 2 to 3 mm below a top surface of thecartilage, for receiving a tissue repair implant. The bone surface canprovide a substantially smooth surface for placement of the implant anda stable structure to which the implant can be attached. Once thearticular surface has been properly prepared, the tissue repair implantcan be implanted into the cavity formed in the cartilage and onto thearticular surface. In some embodiments, a portion of the bone can beremoved, and the implant can be implanted into the cavity formed in thecartilage and in the bone.

Before the implant is placed into a patient, the implant can be createdusing viable tissue, e.g., living, non-destroyed tissue cells, harvestedfrom the patient in a first surgical procedure separate from a surgicalprocedure in which the implant is delivered to the patient, such as inautologous chondrocyte implantation (ACI) procedure, e.g., a procedureusing a MACI® implant (available from Genzyme Corporation of Cambridge,Mass.). Although, a person skilled in the art will appreciate that theviable tissue can also or instead be gathered during the same surgicalprocedure in which the implant is attached to the patient.

Viable tissue can be collected from the patient in any way, as will beappreciated by a person skilled in the art. Various non-limitingembodiments of methods and devices for collecting tissue from a patient,such as in a biopsy procedure, can be found in U.S. Pat. No. 7,115,100issued Oct. 3, 2006 entitled “Tissue Biopsy And Processing Device,” U.S.Patent Publication No. 2008/0234715 filed Mar. 27, 2008 entitled “TissueExtraction and Collection Device,” and U.S. Patent Publication No.2005/0059905 filed Sep. 11, 2003 entitled “Tissue Extraction andMaceration Device,” which are hereby incorporated by reference in theirentireties.

The source of viable tissue can vary, and the tissue can have a varietyof configurations, but in an exemplary embodiment the harvested tissueincludes chondrocytes. In an exemplary embodiment, once a sample ofviable tissue has been obtained, the tissue sample can be processedunder sterile conditions to create a suspension having at least oneminced, or finely divided tissue particle. It is also possible toharvest the tissue in minced form such that further processing is notnecessary. A person skilled in the art will appreciate that mincedviable tissue fragments are simply small portions of living,non-destroyed tissue and that minced tissue fragments can enhance theeffectiveness of the regrowth and healing response. The particle size ofeach tissue fragment can vary. By way of non-limiting example, thetissue size can be in the range of about 0.001 to 3 mm³, but preferablythe tissue particle is less than about 1 mm³. In another embodiment, theviable tissue can be in the form of a tissue slice or strip harvestedfrom healthy tissue that contains viable cells capable of tissueregeneration and/or remodeling, as described in U.S. Patent PublicationNo. 2005/0125077 filed Dec. 5, 2003 and entitled “Viable Tissue RepairImplants and Methods of Use,” which is hereby incorporated by referencein its entirety. The tissue slice can be harvested to have a geometrythat is suitable for implantation at the site of the injury or defect,and the harvested tissue slice can be dimensioned to allow the viablecells contained within the tissue slice to migrate out and proliferateand integrate with tissue surrounding the repair site. A person skilledin the art will appreciate that tissue can be collected from the patientand/or a compatible donor, that the tissue can be artificial tissuematerial, and that any combination of harvested tissue and artificialtissue material can be used.

Viable tissue harvested from a patient can optionally be combined with avariety of other materials, including carriers, such as a gel-likecarrier or an adhesive. The viable tissue can also be contacted with amatrix-digesting enzyme to facilitate tissue migration out of theextracellular matrix surrounding the viable tissue. The enzymes can beused to increase the rate of cell migration out of the extracellularmatrix and into the implant. Various non-limiting embodiments ofgel-like carriers, adhesives, and enzymes can be found in U.S. PatentPublication No. 2005/0177249 filed Feb. 9, 2004 entitled “Scaffolds WithViable Tissue,” which is hereby incorporated by reference in itsentirety. Other non-limiting embodiments of viable tissue sources andmethods for preparing viable tissues are disclosed in U.S. PatentPublication No. 2005/0113937 filed on Nov. 26, 2003 entitled“Conformable Tissue Repair Implant Capable Of Injection Delivery,” whichis hereby incorporated by reference in its entirety.

The viable tissue and any material combined with the viable tissue canbe loaded onto a tissue scaffold. The scaffold can have a variety ofconfigurations, as will be appreciated by a person skilled in the art.Generally, the scaffold can be formed using virtually any material ordelivery vehicle that is biocompatible, bioimplantable, easilysterilized, and that has sufficient structural integrity and/or physicaland mechanical properties to effectively provide for ease of handling inan operating room environment and to permit it to accept and retain oneor more securing mechanisms, e.g., sutures, staples, adhesive, etc.,without substantially tearing. By way of non-limiting example, thescaffold can be in the form of a matrix that is formed from a variety ofany one or more materials, including resorbable materials,non-biological materials, and/or synthetic materials. The scaffold canbe flexible so as to allow the scaffold to conform to the shape anddimensions of the target site of implantation. The scaffold can alsoinclude a bioabsorbable and/or bioresorbable component to act as atemporary carrier to improve handling of the implant duringtransportation. Various non-limiting embodiments of tissue scaffolds canbe found in previously mentioned U.S. Patent Publication No.2005/0177249 filed Feb. 9, 2004 entitled “Scaffolds With Viable Tissue,”and in U.S. Patent Publication No. 2004/0078090 filed Feb. 25, 2003entitled “Biocompatible Scaffolds With Tissue Fragments,” U.S. PatentPublication No. 2005/0038520 filed Aug. 11, 2003 entitled “Method AndApparatus For Resurfacing An Articular Surface,” and U.S. Pat. No.6,884,428 issued Apr. 26, 2005 entitled “Use of Reinforced Foam Implantswith Enhanced Integrity For Soft Tissue Repair And Regeneration,” whichare hereby incorporated by reference in their entireties.

Tissue harvested from a patient can be prepared and applied to ascaffold in any way, as will be appreciated by a person skilled in theart. The tissue component can be added to the scaffold during or aftermanufacture of the scaffold or before or after the implant is installedin a patient. Optionally, a bioactive agent can be incorporated withinand/or applied to the tissue scaffold, and/or it can be applied to theviable tissue. Preferably, the bioactive agent is incorporated within,or coated on, the scaffold prior to the addition of viable tissue to thescaffold. The bioactive agent(s) can be selected from among a variety ofeffectors and cells that, when present at the site of injury, promotehealing and/or regeneration of the affected tissue. Various non-limitingembodiments of effectors and cells can be found in previously mentionedU.S. Patent Publication No. 2005/0177249 filed Feb. 9, 2004 entitled“Scaffolds With Viable Tissue.” Various non-limiting embodiments ofapplying tissue, e.g., minced viable tissue, to a scaffold can be foundin U.S. Patent Publication No. 2004/0193071 filed Mar. 28, 2003 entitled“Tissue Collection Devices And Methods,” which is hereby incorporated byreference in its entirety.

As mentioned above, once a tissue scaffold is available for implantationinto a patient, the patient can be prepared for the scaffold'simplantation by removing defective cartilage to create a hole or cavityin the cartilage that extends from a surface of the cartilage to theunderlying femoral condyle, or other site, as mentioned above. Thedefect site can be prepared for scaffold implantation in a variety ofways. In one exemplary embodiment, a surgical cutting tool configured tocut a predetermined shape in tissue can be arthroscopically used to forma cut having a predetermined shape in the cartilage such that the cutshape encloses the lesion. Cartilage can be removed from within the cutshape such that the cut shape can define a perimeter of the tissuecavity in which the scaffold can be implanted. In some embodiments, thecutting tool can be used to cut multiple shapes in the cartilage, eachof the shapes overlapping at least a portion of the lesion andoptionally overlapping at least one additional cut shape. The shapes canalso be altered and/or connected using the same and/or additionalcutting tools. The cartilage within the combined cut shape can beremoved to define the shape of the scaffold-receiving cavity. Variousnon-limiting embodiments of preparing tissue, including forming ascaffold-receiving cavity in tissue, can be found in U.S. patentapplication Ser. No. 12/412,492 entitled “Methods And Devices ForPreparing And Implanting Tissue Scaffolds” filed on Mar. 27, 2009, whichis hereby incorporated by reference in its entirety. A person skilled inthe art will appreciate that other cutting tools or free-hand techniquescan be used to prepare the defect site.

With defective tissue cleared as desired to form a cavity, an implantcan be prepared for delivery to and optionally fastening within thecavity. An implant is traditionally created larger than an expected sizeof the cavity, e.g., a size larger than the defect site, and cut duringthe surgical procedure to a size and shape substantially matching thecavity. In this way, the implant can be cut from a portion of theprepared tissue replacement implant that includes a high concentrationof deposited viable tissue, as tissue often adheres in varyingconcentrations across a tissue replacement implant. Moreover, the sizeof the cavity formed during a surgical procedure can be greater or lessthan expected, e.g., if the defect site is larger than previouslydetermined, if more healthy tissue is removed than originally intended,etc. Cutting an implant to size during the procedure can thus help matchthe implant's size to the cavity's actual size.

The tissue replacement implant can be trimmed to a desired size andshape in any number of ways. In one exemplary embodiment, a tissuereplacement implant can be cut from a larger prepared implant using acutting tool configured to cut a predetermined shape that corresponds toa predetermined shape cut in tissue at the defect site. In anotherexemplary embodiment, a template tool can be used to size the defect andhelp cut a desirably sized tissue replacement implant. The template toolcan have a variety of configurations, e.g., an adjustable template toolhaving at least one adjustable opening or a flexible film, and can beused in a variety of ways to size an implant. Various non-limitingembodiments of methods and devices for trimming a tissue scaffold to adesired size and shape can be found in previously mentioned U.S. patentapplication Ser. No. 12/412,492 entitled “Methods And Devices ForPreparing And Implanting Tissue Scaffolds” filed on Mar. 27, 2009.

Regardless of how a cavity is formed in tissue and regardless of how atissue replacement implant is created and cut to a desired size to fitin the cavity, the implant can be delivered into the cavity and affixedto bone and/or calcified cartilage in any way. In an exemplaryembodiment, illustrated in FIG. 1, tools configured to deliver a tissuescaffold 10 to a site of attachment can include a delivery shaft 12configured to be slidably received in a delivery cannula 14 having afunnel 16 removably coupled to a distal end 14 a thereof. As discussedfurther below, the funnel 16 can be configured to move the scaffold 10attached to a distal end 12 a of the shaft 12 from a planarconfiguration outside the cannula 14 to a U-shaped folded configurationinside the cannula 14. With at least a portion of the shaft 12 havingthe scaffold 10 attached thereto disposed inside the cannula 14, thecannula 14 can be inserted into a body of a patient. The shaft 12 can bedistally advanced through the cannula 14, thereby distally advancing thescaffold 10 out of the distal end 14 a of the cannula 14 and into thepatient. Advancing the scaffold 10 from the cannula 14 can also move thescaffold 10 from the folded configuration to the planar configuration inwhich the scaffold 10 can be attached to a tissue defect site.

Although the tissue scaffold 10 is illustrated as having an oblong shapeand as a tissue matrix having viable tissue disposed on one side thereofand having a plurality of pores 10 a formed therethrough, the scaffold10 can have a variety of shapes, sizes, and configurations. In someembodiments, the scaffold 10 can have a thickness of less than about 3mm and a surface area of about 10 cm² (1000 mm²) to conform to atraditionally-sized tissue defect site.

The delivery shaft 12 can also have a variety of sizes, shapes, andconfigurations. In this embodiment, shown in FIGS. 2A and 2B, thedelivery shaft 12 can be configured similar to a fork and it can includean elongate body 18 having at least one prong 20 at the distal end 12 aof the shaft 12. The shaft 12 can have any longitudinal length, but inan exemplary embodiment the shaft 12 can be longer than the cannula 14to allow the shaft 12 to be disposed in an inner lumen or passageway 22extending through the cannula 14 and simultaneously distally extendbeyond the cannula's distal end 14 a and proximally extend beyond aproximal end 14 b of the cannula 14 (see FIGS. 10 and 11). A proximalend 12 b of the elongate body 18 can have a tapered cone shape, e.g., betapered in proximal direction, as shown, to help introduce the shaft 12proximal end 12 b first through the funnel 16 in the distal end 12 a ofthe cannula 12, as discussed further below. One or more portions of theshaft 12 can optionally include one or more gripping mechanisms, e.g.,molded finger depressions, treads, etc., to facilitate handling andmanipulation of the shaft 12.

The one or more prongs 20 at the shaft's distal end 12 a can generallybe configured to penetrate and extend through a tissue scaffold, e.g.,the scaffold 10, to attach the scaffold 10 to the shaft 12 for deliveryinto a body of a patient. The one or more prongs 20 can have any size,shape, and configuration and can be configured with sufficient strengthsuch that the shaft 12 can serve as a bone preparation tool. In anexemplary embodiment, each prong 20 has a longitudinal length 201greater than a thickness of a tissue scaffold to which the prong 20 isconfigured to be attached, and more preferably the length 201 of eachprong 20 is sufficient to allow the scaffold to fold around the prongs20 without the scaffold falling off, as discussed further below. In anexemplary embodiment, the length 201 of each prong 20 is in a range ofabout 15 to 35 mm. In an exemplary embodiment, each of the prongs 20also has a diameter D3 that is equal to or less than a diameter of atissue scaffold to which the prongs 20 are configured to be attached tohelp prevent the prongs 20 from damaging the scaffold. In an exemplaryembodiment, the diameter D3 of the prongs 20 is in a range of about 0.1to 2 mm, e.g., about 0.5 to 1 mm. Although two prongs 20 are shown, thedelivery shaft 12 can include any number of prongs 20. Moreover, each ofthe prongs 20 can be the same or different from any other of the prongs20. The prongs 20 can be configured as spikes or pins as shown, with orwithout tapered distal tips configured to help the prongs 20 penetrate atissue scaffold. The prongs 20 can be arranged at the shaft's distal end12 a in any configuration, such as equidistantly spaced radially arounda central longitudinal axis A of the shaft 12, as illustrated. In anembodiment where the shaft 12 has a single prong, the single prong canbe substantially axially aligned with the central longitudinal axis A,or in other embodiment it can be offset from the axis A.

Although the prongs 20 are shown integrally formed with the elongatebody 18 (they appear detached in the exploded view shown in FIG. 2A),any one or more of the prongs 20 can be movably coupled to the elongatebody 18. In some embodiments, the prongs 20 can be retractable such thatin an extended position the prongs 20 can extend distally beyond theelongate body's distal end and in a retracted position can be containedwithin the elongate body 18. Retraction and extension of movable prongscan be controlled in any way, as will be appreciated by a person skilledin the art, such as through actuation of a control mechanism, e.g., aknob, a button, a lever, an electronic signal communicator, etc., at theproximal end 12 b of the shaft 12. Alternatively or in addition to beingretractable, the one or more prongs 20 can be modular elementsconfigured to be removably coupled to the elongate body 18 in any wayappreciated by a person skilled in the art, e.g., threadably attached,snap fit, etc. In this way, prongs of different sizes, e.g., havingdifferent diameters, can be coupled to the elongate body 18 to allow theshaft 12 to more effectively attach to various tissue scaffolds duringthe same or different surgical procedures. Modular prongs can optionallybe supplied with a delivery shaft as part of a kit, which can alsoinclude a delivery cannula and a funnel.

Although the shaft 12 can be a solid member as shown, the shaft 12 caninclude one or more passageways formed therethrough. For non-limitingexample, the shaft 12 can include a tunnel extending through its distaland proximal ends 12 a, 12 b that is configured to receive at least onesurgical instrument disposed therethrough, e.g., a vacuum deviceconfigured to suction fluid, tissue, etc. away from a surgical site.

The shaft 12 can also optionally include a locking feature 24 locatedbetween the distal and proximal ends 12 a, 12 b and configured to beengaged by a corresponding locking mechanism on the cannula 14,discussed below, to retain the shaft 12 at a predetermined positionwithin a passageway 22 of the cannula 14. The locking feature 24 can belocated anywhere along a longitudinal length of the shaft 12. To helpposition the at least one prong 20 within the cannula 14, a longitudinallength L1 between a distal-most end of the shaft 12 and the lockingfeature 24 can be less than a longitudinal length between a distal-mostend of the cannula 14 and the cannula's locking mechanism.

The locking feature 24 can have a variety of shapes, sizes, andconfigurations. In the illustrated embodiment, the locking feature 24 isin the form of an annular groove formed in a surface of the elongatebody 18 around a circumference of the body 18. The groove can be taperedto prevent movement of the shaft 12 within the cannula 14 when thelocking feature 24 is engaged by its cannula counterpart. Because in theillustrated embodiment the shaft 12 is configured to be advancedproximal end 12 b first into the distal end 14 a of the cannula 14 andadvanced through the passageway 22 proximally to load the shaft 12therein, the groove tapers outward in a distal to proximal direction toform a perpendicular stop surface 23 that stops proximal movement of theshaft 12 when the locking feature 24 is engaged by its cannulacounterpart. The proximal tapering can also allow the shaft 12 to beadvanced distally when distal pressure is applied thereto, as discussedfurther below. A person skilled in the art will appreciate that whilethe locking feature 24 can be a radial groove formed around acircumference of the elongate body 18 as shown, various other lockingtechniques can be used and can be formed on any portion of the shaft 12and/or cannula 14.

The locking feature 24 can be configured to be engaged by acorresponding locking mechanism, discussed further below, formed on orotherwise coupled to the cannula 14 when the shaft 12 is advanced intothe cannula 14. The locking mechanism and the locking feature 24 canthereby releasably lock the shaft 12 in the passageway 22 at apredetermined location relative to the cannula 14. In this way, the atleast one prong 20 configured to attach to a tissue scaffold can bepredictably and effectively contained within the passageway 22 for safedelivery into a body of patient.

The tissue scaffold 10 can be attached to the distal end 12 a of theshaft 12 in a variety of ways, as will be appreciated by a personskilled in the art. In one embodiment, a grasper can hold the scaffold10 as the prongs 20 of the shaft 12 are passed through the scaffold 10.A person skilled in the art will appreciate that the term “grasper” asused herein is intended to encompass any surgical instrument that isconfigured to grab and/or hold the scaffold 10 such as forceps,retractors, movable jaws, magnets, adhesives, etc. In anotherembodiment, a loading block can be used to help predictably position theprongs 20 relative to the scaffold 10. FIGS. 3-7 illustrate oneexemplary embodiment of a loading block 26 configured to help attach thetissue scaffold 10 to the delivery shaft 12.

Generally, the loading block 26 can include a main body 26 a and a guidemember 26 b positioned at least partially above the main body 26 a. Themain body 26 a can include a top, tissue-receiving surface 28 configuredto receive a tissue scaffold thereon. The top surface 28 can have one ormore openings 30 formed therein that extend at least partially through athickness t of the main body 26 a and that are each configured toreceive a prong of a delivery shaft therein. When a tissue replacementimplant is placed on the top surface 28, the prongs can be guidedthrough one or more channels 32 formed in a portion of the guide member26 b positioned over the main body 26 a and can thereby be guidedthrough the scaffold and at least partially into the openings 30. Thedelivery shaft with the scaffold attached thereto can then be removedfrom the loading block 26 and used to introduce the scaffold into a bodyof a patient, as discussed further below.

While the loading block 26 can be made from any combination of rigidand/or flexible materials, in an exemplary embodiment the block 26 iscomposed of one or more rigid materials, e.g., RadelR® polyphenylsulfoneavailable from Solvay Advanced Polymers, L.L.C. of Alpharetta, Ga., sothe block 26 does not deform during use, which can improve chances ofstable, predictable scaffold loading using the block 26. The block 26can have dimensions appropriate for use with any size tissue replacementimplant and any size delivery guide to which the tissue replacementimplant is to be attached using the block 26. In an exemplaryembodiment, as illustrated, the block 26 has a longitudinal length h ofabout 1.4 in. (35.6 mm), a width w of about 0.8 in. (20.3 mm), and aheight h of about 0.85 in. (21.6 mm). The main body 26 a and the guidemember 26 b of the loading block 26 can have a variety of sizes, shapes,and configurations. In the illustrated embodiment, the block 26 has arectangular box-shaped main body 26 a with an L-shaped guide member 26 bextending from the top, tissue-receiving surface 28.

The top, tissue-receiving surface 28 of the main body 26 a can have avariety of sizes, shapes, and configurations. The top surface 28 canhave any shape and surface area that is generally large enough toreceive a tissue scaffold thereon. The top surface 28 can be configuredto be large enough such that edges of a scaffold placed thereon do notextend beyond any of the edges of the top surface 28 to help more stablyposition the scaffold on the block 26. The top surface 28 can in someembodiments have a surface area greater than about 3 cm² (300 mm²). Inthe illustrated embodiment, the top surface 28 has a surface area ofabout 0.94 in.² (606 mm²). The top surface 28 can be rectangular asshown, or it can have any other shape, e.g., elliptical, square, etc.The top surface 28 can be substantially planar to allow a tissuescaffold to rest substantially flat thereon. A person skilled in the artwill appreciate that the top surface 28 can longitudinally extend in asingle plane such that the main body 26 a has a constant thickness t asshown, or the top surface 28 can extend at an angle in any direction ordirections with the main body 26 a having a varying thickness t. In theillustrated embodiment, the thickness t is about 0.42 in. (10.7 mm). Ifthe top surface 28 is angled, it can angle towards the guide member 26 bsuch that the thickness t of the main body 26 a decreases toward theguide member 26 b, which can help position an edge of a tissue scaffoldon the top surface 28 against a facing surface 34 of the guide member 26b that faces the top surface 28, as discussed further below.

The openings 30 in the top surface 28 can also have any size, shape, andconfiguration. The openings 30 can be configured to receive the prongs20 of the shaft 12, and can thus have a size large enough to accommodateentry of the prongs distal end first into the openings 30. The openings30 can be separated by a distance w2, which is about 0.157 in. (4.0 mm)in this illustrated embodiment, and which corresponds to the distancebetween the prongs 20 on the delivery shaft 12. The distance w2 can,however, vary depending on the delivery shaft used therewith. Asillustrated, the openings 30 are each configured as elongate oblongslots extending longitudinally along the top surface 28 and having alongitudinal length 301 of about 0.4 in. (10.2 mm) and a width w3 ofabout 0.065 in. (1.7 mm), although the openings 30 can have anyorientation, size, and shape, e.g., circular, square, rectangular, etc.The openings 30 can also have any depth extending at least partiallythrough the thickness t of the main body 26 a and can generally beconfigured to be deep enough such that the penetration of the prongs 20through the scaffold 10 is not limited. Although two openings 30 areillustrated in this embodiment, the block 26 can include any number ofopenings 30. Moreover, each of the openings 30 can be the same ordifferent from any other of the openings 30. The block 26 can alsoinclude more openings 30 than a number of prongs that extend through atissue replacement implant on the top surface 28.

The top surface 28 can optionally include a label 36 configured toprovide information related to the loading block 26. Although the label36 is shown as alphabetical characters printed, embossed, or otherwiseviewable on the top surface 28, a person skilled in the art willappreciate that the label 36 can have any size, shape, andconfiguration, such as any combination of colors or alphabetical,numerical, and symbolic characters. A person skilled in the art willalso appreciate that the block 26 can include any number of labels andthat each label can be printed, embossed, or otherwise viewable on anyportion of the loading block 26 in addition or in alternative to the topsurface 28. In the illustrated embodiment, the label 36 identifies asuggested positioning of a tissue scaffold to be received thereon withwritten instructions to place a tissue scaffold on the top surface 28with a tissue side of the scaffold face down, which can help inprotecting viable tissue generally deposited on one side of the tissuescaffold during implantation of the tissue scaffold as discussed furtherbelow. Another non-limiting example of the label 36 includes dimensionsof various components of the block 26, such as the top surface 28, theopenings 30, and the channels 32.

As mentioned above, the guide member 26 b extending from the main body26 a of the block 26 is L-shaped, although it can have a variety ofsizes, shapes, and configurations. As illustrated in this embodiment,the guide member 26 b includes a first arm 38 extending substantiallyperpendicular from the main body 26 a, and a second arm 40 extendingsubstantially perpendicular from the first arm 38 and extending over themain body 26 a such that the second arm 40 is substantially parallel tothe top surface 28 of the main body 26 a. The location of the first arm38 on the top surface 28 can vary, but in the illustrated embodiment thefirst arm 38 extends from a terminal end 28 a of the top surface 28.Either of the first and second arms 38, 40 can have a longitudinallength longer than the other, or their longitudinal lengths can be thesame, but in this illustrated embodiment the first arm 38 has a longerlongitudinal length l₃ of about 0.43 in. (10.9 mm) than the second arm'slongitudinal length l₄ of about 0.177 in. (4.5 mm). The second arm'slongitudinal length l₄ can define a predetermined distance from aperimeter of the scaffold 10 placed on the top surface 28 that theprongs 20 of the delivery shaft 12 can be advanced through the scaffold10. The second arm's longitudinal length l₄ can thus be configured toallow the scaffold 10 to fold around the prongs 20 when advanced intothe cannula 14, as discussed further below. The longitudinal length l₃can be selected in relation to a length of the prongs 20 if the shaft12, so that a scaffold positioned on the block 26 ends up at a desiredposition on the prongs 20, e.g., about half length in this illustratedembodiment.

As previously indicated, the guide member 26 can also include one ormore channels 32 formed therein for guiding the prongs 20 into theopenings 30. The channels 32 formed in the guide member 26 b can alsohave a variety of sizes, shapes, and configurations. Generally, thechannels 32 can be configured to each receive a prong of a deliveryshaft therein and guide the prong therethrough in a predetermineddirection to a predetermined position, e.g., toward one of the openings30 in the top surface 28. In this way, the prongs can be advancedthrough a scaffold on the top surface 28 at a predictable, desirableposition.

The channels 32 can be axially aligned with the openings 30 in aone-to-one relationship where each channel 32 is associated with oneopening 30. Although two channels 32 are illustrated in this embodimentto correspond with the two openings 30, the block 26 can include anynumber of channels 32 more or less than the number of openings 30 formedin the loading block 26. Moreover, each of the channels 32 can be thesame or different from any other of the channels 32. The block 26 caninclude more channels 32 than a number of prongs on a delivery shaftthat are extended through the guide member 26 b and into a tissuereplacement implant on the top surface 28. The channels 32 can beseparated by the distance w2 equal to the distance separating theopenings 30 to align the channels 32 with the openings 30. Asillustrated, the channels 32 are each configured as semi-cylindricalcut-outs extending through the second arm 40 of the guide member 26 a ina direction substantially perpendicular to a face of the top surface 28.The channels 32 can, however, have any size, shape, and orientationrelative to the top surface 28. The channels 32 can have any depthextending into the guide member 40 configured to provide enough of apathway along which a surgical tool can be guided. The channels 32 canalso have any longitudinal length l₅, although they can be configured tobe shorter than prongs of a delivery shaft to be received therein toallow at least a portion of the prongs to extend along the channels 32and have their distal-most ends of the prongs received in the openings30. As illustrated, the channels 32 can extend along one surface of theguide member 40 and have a longitudinal length l₅ equal to the width ofthe guide member's second arm 40, e.g., about 0.08 in. (2.0 mm).

In use, as illustrated in one embodiment in FIG. 8, the block 26 can beused to attach the scaffold 10 to the prongs 20 of the delivery shaft12. Using the block 26 to attach the scaffold 10 to the delivery shaft12 can position the prongs 20 through the scaffold 10 at a predeterminedlocation on the scaffold 10, thereby helping to safely deliver thescaffold 10 into the body of a patient, as discussed further below.Although use of the loading block 26 is described with reference to thescaffold 10 and the shaft 12 of FIG. 1, a person skilled in the art willappreciate that the loading block 26 can be used with these or any otherimplant and delivery device.

To prepare the scaffold 10 for attachment to the delivery shaft 12, thescaffold 10 can be positioned on the main body's top surface 10 in asubstantially planar position. As discussed above, the scaffold 10 canbe placed on the top surface 28 with a side of the scaffold 10 havingviable tissue disposed thereon face down on the top surface 28 withanother, opposite side of the scaffold 10 facing up. The scaffold 10 canbe positioned anywhere on the top surface 28, but as shown in theillustrated embodiment, the scaffold 10 can be positioned such that aportion of its perimeter abuts the facing surface 34 of the guide member26 b at the terminal edge 28 a of the top surface 28 where the topsurface 28 meets the guide member 26 b. The scaffold 10 can also bepositioned with its major axis substantially parallel to longitudinallengths of the openings 30. In this way, the scaffold 10 can bepredictably positioned on the top surface 28 over the openings 30 andunder the channels 32 with a predetermined length of the scaffold 10extending between the terminal edge 28 a and the openings 30, e.g., thelongitudinal length l₄ of the second arm 40 underneath which thescaffold 10 can be positioned.

With the scaffold 10 positioned as desired on the top surface 28 of theblock 26, the prongs 20 of the delivery shaft 12 can be distallyadvanced along the channels 32 toward the scaffold 10 and insertedthrough the scaffold 10 to attach the scaffold 10 thereto. In this way,each of the prongs 20 can be guided through the scaffold 10, optionallywith distal-most tips of the prongs 20 helping to pierce the scaffold 10and/or the prongs 20 passing through the pores 10 a of the scaffold 10.Because the channels 32 can be axially aligned with the openings 30, theprongs 20 can each be received in one of the openings 30 after passingthrough the scaffold 10. The longitudinal lengths of the prongs 20 canbe long enough to allow the prongs 20 to simultaneously extend throughthe channels 32 and at least partially into the openings 30. Distalmovement of the shaft 12 can be limited by a stop mechanism, such as abottom surface of one or more of the openings 30 and/or by a top surface42 of the guide member 26 b. The top surface 42 of the guide member 26 bcan stop distal movement of the shaft 12 when the distal surface of theelongate body 18 of the shaft 12, e.g., the surface of the body 18 fromwhich the prongs 20 extend, contacts the guide member's top surface 42.By limiting distal movement of the shaft 12 in any one or more ways, theprongs 20 can be advanced through the scaffold 10 by a sufficient amountsuch that the scaffold 10 can be adequately attached to the prongs 20.

With the prongs 20 extending through the scaffold 10, the delivery shaft12 can be disengaged from the block 26 with the scaffold 10 attachedthereto. The shaft 12 can be moved in a direction away from the topsurface 28 along the longitudinal axis A of the shaft 12 to disengagethe prongs 20 from the openings 30 and hence the shaft 12 from the block26. Optionally, the prongs 20 can be slid through the openings 30 in adirection away from the guide member 26 b to help remove the shaft 12and the scaffold 10 from the block 26, which can help ensure that theposition of the scaffold 10 on the prongs 20 does not change duringdisengagement of the prongs 20 from the block 26. The prongs 20 canslide through the openings 30, such as in the illustrated embodiment,when the openings 30 are configured as elongate slots. By sliding theprongs 20 through the openings 30 away from the guide member 26 b, thescaffold 10 can also be moved away from the guide member 26 b and inparticular out from underneath the second arm 40, thereby minimizingchances of the scaffold 10 hitting the second arm 40 when being removedfrom the top surface 28. Such sliding of the prongs 20 can thus beparticularly effective before the shaft 12 is substantially moved in adirection along the longitudinal axis A of the shaft 12. Further,sliding the scaffold 10 in a substantially planar position rather thanangling the scaffold 10 to avoid contact between the guide member 26 band the scaffold 10 can more carefully handle the fragile scaffold 10and help retain viable tissue on the scaffold 10. The shaft 12 canoptionally be slid in the openings 30 and pivoted against the second arm40 to simultaneously slide and lift the scaffold 10.

With the scaffold 10 attached to the shaft 12 via the prongs 20,friction can hold the scaffold 10 on the prongs 20, as shown in FIG. 9,until the scaffold 10 is removed therefrom. The scaffold 10 attached tothe shaft 12 can be delivered to a body cavity of a patient in a varietyof ways, as will be appreciated by a person skilled in the art. In anexemplary embodiment, as mentioned above, the delivery shaft 12 with thescaffold 10 attached thereto can be disposed in the cannula 14 todeliver the scaffold 10 to a tissue defect site for implantation.

The cannula 14 can have a variety of sizes, shapes, and configurations.In the embodiment, shown in FIGS. 10 and 11, the cannula 14 has alongitudinal length L2 and includes an elongate body 44 having a head 46at the proximal end 14 b of the cannula 14. The cannula's elongate body44 can be substantially cylindrical-shaped, as shown, although theelongate body 44 can have any shape. The elongate body 44 can also haveany size such that its longitudinal length can allow at least a portionof the elongate body 44 to be inserted into a body cavity of a patientwith at least the head 46 of the cannula 14 being located outside thepatient. The inner passageway 22 of the cannula 14 can extendlongitudinally through the elongate body 44 and can have any size andshape, e.g., cylindrically-shaped, that is configured to allow thedelivery shaft 12 to be slidably disposed therein. The inner passageway22 can have a constant diameter D2, or the passageway 22 can have avariable diameter D2, e.g., having a larger diameter D2 in at least adistal portion of the elongate body 44 to help accommodate the shaft 12and the scaffold 10. The elongate body 44 can have a substantiallyconstant outer diameter D4 as shown, or the distal end 14 a of theelongate body 44 can have a tapered cone shape, e.g., be tapered in adistal direction, to help introduction of the cannula's distal end 14 afirst into a patient. One or more portions of the elongate body 44and/or the head 46 can optionally include one or more grippingmechanisms, e.g., molded finger depressions, treads, etc., facilitatehandling and manipulation of the cannula 14.

As mentioned above, the shaft 12 can be configured to be disposed in thecannula 14 with the shaft's elongate body 18 slidably received withinthe inner passageway 22 of the cannula 14. The shaft's elongate body 18can thus, as shown in this embodiment, be substantiallycylindrical-shaped to match the shape of the cannula's inner passageway22. The corresponding cylindrical shapes in the cannula's passageway 22and shaft's elongate body 18 can allow the shaft 12 to be both linearlyand rotatably movable within the inner passageway 22, which can helpposition the scaffold 10 at a defect site, discussed further below. Theshaft's elongate body 18 can thus have a diameter D1 less than thediameter D2 of the cannula's inner passageway 22 to allow the elongatebody 18 to be movable therein.

The head 46 is illustrated as being located at a proximal-most end ofthe cannula 14, but the head 46 can be located anywhere at the cannula'sproximal end 14 b. The head 46 can be, for non-limiting example,substantially cylindrically-shaped as shown, although as will beappreciated by a person skilled in the art, the head 46 can have anysize, shape, and configuration. The head 46 can serve as a handleconfigured to allow the cannula 14 to be manipulated outside the body ofa patient. A diameter D5 of the head 46 can be larger than the diameterD4 of the elongate body 44, as shown, which can help the head 22 serveas a handle and help provide a locking mechanism configured toreleasably hold the delivery shaft 12 in a fixed position in thepassageway 22.

The cannula's locking mechanism can have a variety of shapes, sizes, andconfigurations but can generally be configured to complement and beeffective with the shaft's locking feature 24 to releasably lock theshaft 12 within the cannula 14. In the illustrated embodiment, thecannula's locking mechanism includes a button 52 coupled to the head 46of the cannula 14 using a pin 50 and a spring 48. The head 46 can havean opening 54 formed in a side surface thereof such that the opening 54is in communication with the passageway 22 extending through the cannula14. The button 52 can extend into the head 46 through the opening 54with a distal end 52 a of the button 52 positioned within the head 46and with a proximal end 52 b of the button 52 positioned outside thehead 46. The spring 48 can be positioned within the head 46 and bias thebutton 52 toward the passageway 22. The pin 50 can extend through a hole56 formed in the head 46 and a hole 58 formed in the button 52 to holdthe button 52 within the opening 54. The hole 58 in the button 52 canhave a diameter than larger than a diameter of the pin 50, which inaddition to the spring-loading of the button 52, can allow the button 52to be movable relative to the pin 50 and the head 46 when the button 52is depressed. In this way, with the button 52 in a depressed, unlockedposition, the passageway 22 can be clear and a surgical tool can befreely slidable therethrough. With the button 52 in a default, lockedposition, a locking member 52 c of the button 52 can contact a surgicaltool disposed within the passageway 22 in the head 46 to lock thesurgical tool therein until the button 52 is moved to the unlockedposition. The locking member 52 c is shown as a cross-bar having aprotrusion 52 d formed thereon. An inner surface of the locking member52 c, which can have any size, shape, and configuration, can beconfigured to engage the locking feature 24 of the shaft 12, while theprotrusion 52 d can be configured to keep the spring 48 aligned.

As mentioned above, the shaft 12 with the scaffold 10 attached theretocan be advanced into the cannula 14 in a variety of ways. In anexemplary embodiment, shown in FIG. 1, the shaft 12 can be advancedproximal end 12 b first into the distal end 14 a of the cannula 14 tohelp minimize a length of the passageway 22 that the scaffold 10 passesthrough to help reduce chances of the scaffold 10 losing viable tissueby scraping against the passageway 22 and to help reduce chances of thescaffold 10 accidentally falling off the prongs 20 through jostling inthe passageway 22. While the shaft 12 can be directly inserted into thecannula 14, in an exemplary embodiment, the shaft 12 can be advancedthrough the funnel 16 coupled to the distal end 14 a of the cannula 14.The funnel 16 can be configured to have a tapering inner lumen orpassageway to move the scaffold 10 from a planar configuration on theprongs 20, e.g., as illustrated in FIG. 9, to a folded configuration onthe prongs 20 inside the cannula 14, as discussed further below.

The funnel 16 can have a variety of sizes, shapes, and configurations.In an exemplary embodiment, illustrated in FIGS. 12 and 13, the funnel16 includes an elongate body having an inner lumen or passageway 60extending between distal and proximal ends 16 a, 16 b thereof. Thefunnel 16 can have any longitudinal length L6, e.g., about 2.36 in.(59.9 mm), any length of which can be advanced over the cannula 14. Thepassageway 60 can have any shape, e.g., a generally cylindrical shape tocorrespond to the shape of the funnel's passageway 60 with the cannula'spassageway 22. The passageway 60 can have a varying diameter such that adiameter D6 of the passageway 60 in a distal portion 60 a of thepassageway 60 is greater than the diameter D6 of the passageway 60 in aproximal portion 60 b of the passageway 60, with the diameter D6tapering proximally inward at a mid-portion 60 c of the funnel 16between the distal and proximal portions 60 a, 60 b. The distal andproximal portions 60 a, 60 b can each have any longitudinal length,e.g., a length L7 of about 0.54 in. (13.7 mm) in the distal portion 60 aand a length L8 of about 1.5 in. (38.1 mm) in the proximal portion 60 b.The diameter D6 of the passageway 60 in the proximal portion 60 b of thefunnel 16 can be slightly greater than the outer diameter D4 of thecannula 14 at least at the distal end 14 a of the cannula 14 to allowthe proximal end 16 b of the funnel 16 to securely fit over the distalend 14 a of the cannula 14, as illustrated in FIG. 1, such that thefunnel's passageway 60 and the cannula's passageway 22 can be incommunication with each other and can provide a smooth transitionbetween the two. The size of the diameter D6 of the funnel's passageway60 can vary, e.g., about ⅔ larger in the distal portion 60 a with adiameter D6 of, e.g., about 0.575 in. (14.6 mm) in the distal portion 60a and about 0.377 in. (9.6 mm) in the proximal portion 60 b. An outerdiameter D7 of the funnel's elongate body can vary, e.g., about 0.688in. (17.5 mm) in the distal portion 60 a and about 0.48 in. (12.2 mm) inthe proximal portion 60 b, or it can be substantially constant. Whilethe funnel 16 can be made from any combination of rigid and/or flexiblematerials, in an exemplary embodiment the funnel 16 is composed of oneor more substantially rigid materials, e.g., medical gradepolycarbonate.

In use, the funnel 16 can be attached to the distal end 14 a of thecannula 14, and the shaft 12 can be slidably received therein. With theshaft 12 advanced proximal end 12 b first into the distal end 16 a ofthe funnel 16 and the distal end 14 a of the cannula 14, the prongs 20can be the last portion of the shaft 12 introduced into the funnel 16and the cannula 14. Because the prongs 20 can be advanced through thescaffold 10 a predetermined distance from an edge of the scaffold 10,e.g., the length l₄, the prongs 20 can be positioned with respect to thescaffold's perimeter to predictably move the scaffold 10 from a planarconfiguration to a folded configuration as the scaffold 10 moves throughthe funnel 16 such that the scaffold 10 can be in the foldedconfiguration within the cannula 14. In other words, the taperedpassageway 60 of the funnel 16 can guide the scaffold 10 into a foldedconfiguration in which the scaffold 10 is wrapped around the prongs 20,e.g., as illustrated in FIG. 14. A person skilled in the art willappreciate that in a folded configuration, the scaffold 10 can berolled, as shown, and/or creased. Moreover, because the scaffold 10 canbe elliptical and loaded onto the prongs 20 with its tissue side 10 bfacing down, e.g., away from the shaft's elongate body 18 as illustratedin FIG. 9, and with the prongs 20 at an asymmetrical location along amajor axis of the scaffold 10, the scaffold 10 can be folded into aU-shape around the prongs 20 with the tissue side 10 b facing the prongs20. In this way, the tissue side 10 b of the scaffold 10 can be betterprotected within the cannula 14 as the shaft 12 with the scaffold 10attached thereto slides through the passageway 22 of the cannula 14.

The shaft 12 can be advanced any distance into the cannula 14 to fullycontain the scaffold 10 within the cannula's passageway 22. In anexemplary embodiment, the locking mechanism cooperating between theshaft 12 and the cannula 14 can allow the shaft 12 to advance apredetermined distance into the cannula 14 to help ensure that theprongs 20 with the scaffold 10 attached thereto are fully, safelycontained within the cannula 14. As discussed above, the lockingmechanism can have a variety of configurations, but in this illustratedembodiment, the button 52 in the head 46 of the cannula 14 can engagethe groove 24 formed in the shaft 12 to hold the shaft 12 in a lockedposition within the cannula 14. As the shaft 12 passes through thepassageway 22 of the cannula 14, the shaft 12 can move the button 52from its biased position to the depressed position. Moving the shaft 12through the passageway 22 in the head 46 can maintain the button 52 inits depressed position, with the shaft 12 passing through an openingformed through the button 52 between the distal and proximal ends 52 a,52 b thereof, until the groove 24 reaches the button 52. When the shaft12 passes an adequate distance through the passageway 22 for the lockingfeature 24 to reach the button 52 such that the locking feature 24 andthe button 52 are aligned, the button 52 can slide into the groove 24,e.g., an inner surface of the locking member 52 c can engage the groove24. The groove 24, having a small diameter than the elongate body 18 inwhich it is formed, can thus help urge the button 52 from the unlockedto locked position, thereby holding the shaft 12 in a fixed positionuntil the button 52 is pressed at its proximal end 52 b and/or the shaft12 is advanced distally such that its tapered shape can disengage thelocking feature 24 from the cannula's locking mechanism. In the lockedposition, at least the proximal end 12 b of the shaft 12 can extendproximally beyond the proximal end 14 b of the cannula 14 to allow theshaft 12 to be manipulated from outside the cannula 14 and outside abody of a patient when the cannula 14 is introduced therein. Also in thelocked position, the prongs 20 with the scaffold 10 attached thereto canbe positioned in a distal portion of the cannula 14 just proximal of thefunnel 16. Thus, in the illustrated embodiment, pushing the elongatebody 18 distally can unlock the parts without requiring manual pushingof the button 52. The stiffness of the spring 48 and the slope of thetaper can determine how much force, which is created to help preventaccidental fall-out of the elongate body 18 from the cannula 14, isrequired to unlock the parts.

Once the shaft 12 and the scaffold 10 are back-loaded into the cannula14, the cannula 14 can be inserted through tissue. A person skilled inthe art will appreciate that the scaffold 10, or any other tissuereplacement implant, can be introduced into a patient in any way. In oneembodiment illustrated in FIG. 15, the cannula 14 can be inserted into abody cavity through a surgically created incision or opening 62 in atissue 64 to prepare for delivery of the scaffold 10 into the patient.The funnel 16 can be removed from the distal end 14 a of the cannula 14before the cannula 14 is inserted into the patient, which can to helpreduce a size of the opening 62. Although the cannula 14 with the shaft12 disposed therein is shown being initially introduced through thetissue 64, a person skilled in the art will appreciate the cannula 14can be introduced through the tissue 64 without the shaft 12 disposed inthe cannula's passageway 22, such as if the shaft 12 with the scaffold10 attached thereto is introduced into the cannula 14 through thecannula's proximal end 14 b. A person skilled in the art will alsoappreciate that the cannula 14 can be inserted directly through thetissue 64 as illustrated to help minimize a size of the opening 62, orthe cannula 14 can be inserted through an introducer device, e.g., anaccess port that has a working channel through which another surgicalinstrument can be advanced.

The distal end 14 a of the cannula 14 can help form the opening 62and/or one or other surgical tools can be used to form the opening 62through the tissue 64, as will be appreciated by a person skilled in theart. The cannula's elongate body 44 can expand the diameter of theopening 62 to about the diameter D4 of the cannula's elongate body 44 asthe elongate body 44 is passed therethrough, thereby helping to minimizethe size of the opening 62 and to reduce patient trauma. Because thescaffold 10 can be fully disposed within the cannula 14 in a foldedconfiguration, it can be inserted into the patient through an opening 62having a diameter that is smaller than a diameter or maximum width ofthe scaffold 10.

The cannula 14 can be longitudinally advanced any distance through thetissue 64 and positioned in any way relative to the tissue 64. Thecannula 14 can also be positioned in any way relative to a cavity 66formed in tissue, e.g., cartilage 68, at a defect site where thescaffold 10 is to be attached. In an exemplary embodiment, the cannula14 can be positioned through the tissue 64 such that a longitudinal axisA2 of the cannula 14 (see FIG. 10) and the longitudinal axis A of theshaft 12 are each substantially perpendicular to the cavity 66. Suchsubstantially perpendicular positioning can help more quickly, safely,and accurately position the scaffold 10 from outside the patient's bodywith respect to the cavity 66.

Once the cannula 14 has been passed through the tissue 64 with, e.g.,the cannula's elongate body 44 positioned within the opening 62 and withthe cannula's distal end 14 a and the head 46 on opposed sides of thetissue 64, the delivery shaft 12 can be distally advanced through thecannula's passageway 22 and out the cannula's distal end 14 a and/or thecannula 14 can be proximally refracted to expose the scaffold 10 todeliver the scaffold 10 into the patient. As shown in one embodiment inFIG. 16, the central longitudinal axes A, A2 of the delivery shaft 12and the cannula 14, respectively, can be aligned substantiallyperpendicular to a desired location, e.g., above the cavity 66. Althoughthe delivery shaft 12 and the cannula 14 can be located anywhere withrespect to the desired location when the scaffold 10 is advanced throughand outside the cannula 14, such substantially perpendicular positioningcan allow the scaffold 10 to be more accurately delivered to the desiredlocation, which can reduce the amount of movement and positioning of thefragile scaffold 10 inside the body. The shaft 12 can be distallyadvanced through the passageway 22 in the cannula 14 in any way, such asby holding the shaft 12 in a substantially static position andproximally moving the cannula 14 or such as shown by holding the cannula14 in a substantially static position and moving the shaft 12 distallytherethrough. In the illustrated embodiment the locking mechanismautomatically disengages upon distal movement of the shaft 12, butalternatively or in addition, the locking mechanism can be manuallydisengaged, e.g., by pressing the button 52 on the cannula's head 46, toallow free slidable movement of the shaft 12 within the cannula 14.

When the scaffold 10 is positioned beyond the distal end 14 a of thecannula 14, the scaffold 10 can move from the folded configuration backto the planar configuration. As will be appreciated by a person skilledin the art, the scaffold 10 can gradually move from the foldedconfiguration, shown in FIG. 16, to the planar configuration, shown inFIG. 17, as the scaffold 10 gradually advances distally beyond thecannula's distal end 14 a. The scaffold 10 can be formed from a materialthat causes the scaffold 10 to automatically move to the planarconfiguration from the folded configuration, but at least one grasperand/or a delivery guide, discussed further below, can optionally be usedto grasp and help unfold the scaffold 10.

With the scaffold 10 positioned beyond the distal end 14 a of thecannula 14, the scaffold 10 can be detached from the prongs 20 of theshaft 12 and positioned in the cavity 66 for attachment thereto.Positioning of the scaffold 10 in the cavity 66, and/or any otherportion of the surgical procedure, can be visualized, e.g., viewedthrough a lens on a scoping device inserted into the patient andpictured on a visualization screen outside the patient's body. While thescaffold 10 can be removed from the prongs 20 while the shaft 12 isdisposed in the cannula 14, in an exemplary embodiment the cannula 14can be removed from the patient before detaching the scaffold 10 fromthe delivery shaft 12. As illustrated in one embodiment in FIG. 17, thecannula 14 can be removed from the body of the patient, leaving thescaffold 10 and at least a portion of the shaft 12 inside the patient.The cannula 14 can be removed from the patient in any way, such as byholding the shaft 12 outside the body and moving the cannula 14proximally as indicated by the directional arrow in FIG. 17. If lockingmechanism is not configured to automatically disengage upon proximalmovement of the cannula 14 to allow the shaft's locking feature 24 topass the cannula's locking mechanism, the locking mechanism can bemanually disengaged such as by pressing the button 52. Optionally, theprongs 20 can be positioned to abut bone and/or calcified cartilage at abottom surface of the cavity 66, providing stability to the shaft 12 asthe cannula 14 is removed from around the shaft 12.

The scaffold 10 can be removed from the prongs 20 in any way, e.g.,holding the scaffold 10 with a grasper and moving the shaft 12 and/orthe grasper to remove the scaffold 10 from the prongs 20. Alternativelyor in addition, the scaffold 10 can be removed from the prongs 20 usinga surgical instrument configured to be advanced over the shaft 12 andconfigured to help affix the scaffold 10 inside the cavity 66, therebyreducing an amount of instrumentation used during the surgical procedureand improving the accuracy of the scaffold's implantation. Such asurgical instrument can have a variety of configurations, such as oneembodiment of a delivery guide 70 illustrated in FIGS. 18-23. Generally,the delivery guide 70 can be configured to remove the scaffold 10 fromthe prongs 20 of the delivery shaft 12, hold the scaffold 10 in a fixedposition at a desired site of implantation, and, without having to beremoved from the patient's body, to guide one or more surgical devicesconfigured to help affix the scaffold 10 to the desired site ofimplantation. The delivery guide 70 can thus help improve efficiency ofthe surgical procedure, help limit movement of the fragile scaffold 10,and help ensure that the scaffold 10 is affixed within the patient at anintended location.

The delivery guide 70 can have a variety of sizes, shapes, andconfigurations. As shown in this embodiment, the delivery guide 70includes an elongate body 72 having an inner lumen or passageway 76extending between distal and proximal ends 70 a, 70 b of the guide 70and having at least one bone-engaging element 74 at the distal end 70 aof the delivery guide 70. The delivery guide 70 can have anylongitudinal length L9, e.g., about 7.2 in. (182.9 mm). In an exemplaryembodiment the delivery guide 70 can be shorter than the delivery shaft12 to allow the shaft 12 to be disposed in the passageway 76 andproximally extend beyond the guide's proximal end 70 b such that theshaft 12 can be more easily manipulated when disposed in the guide 70.The longitudinal length L9 of the guide 70 can also be sufficiently longto allow its distal and proximal ends 70 a, 70 b to be disposed onopposed sides of a tissue surface when the guide 70 is disposed throughthe tissue surface, such as shown in FIG. 26 discussed below.

The elongate body 72 can optionally include one or more grippingmechanisms, e.g., finger loops, molded finger depressions, treads, etc.,to facilitate holding and manipulation of the guide 70. The guide 70 canalternatively or additionally optionally include a handle at itsproximal end 70 b and/or other portion of the elongate body 72. Thehandle can be, for non-limiting example, a substantially cylindricaldisc or knob, although as will be appreciated by a person skilled in theart the handle can have any size, shape, and configuration that allowsthe guide 70 to be held outside the body. A person skilled in the artwill appreciate that the guide 70 need not include a handle but insteadcan be manipulated using, e.g., a proximal portion of the elongate body72.

The one or more bone-engaging elements 74 at the guide's distal end 70 bcan generally be configured to penetrate the scaffold 10, and/orpartially penetrate into bone and/or calcified cartilage, to help securethe guide 70, and thus the scaffold 10, against bone and/or calcifiedcartilage with or without a surgical device present in the guide'spassageway 76. The bone-engaging elements 74 can have any configuration.In the illustrated embodiment the guide 70 includes four bone-engagingelements 74, but the guide 70 can include any number of bone-engagingelements 74, e.g., two. Moreover, each of the bone-engaging elements 74can be the same or different from any other of the bone-engagingelements 74. The bone-engaging elements 74 can be configured as teeth orprongs as shown, with or without tapered distal tips configured to helpthe bone-engaging elements 74 engage bone and/or calcified cartilage.The bone-engaging elements 74 are illustrated as isosceles triangleshaving a height 74 h of about 0.06 in. (1.5 mm), a length 74 l of about0.03 in. (0.75 mm), and a thickness of about 0.01 in. (0.25 mm), but thebone-engaging elements 74 can have any size and shape. The bone-engagingelements 74 can be arranged at the guide's distal end 70 a in anyconfiguration, such as equidistantly spaced radially around a centrallongitudinal axis A3 of the guide 70 along the guide's perimeter, asillustrated in FIG. 23. The bone-engaging elements 74 can extendsubstantially parallel to the guide's longitudinal axis A3 or, asillustrated, the bone-engaging elements 74 can angle radially inwards atan angle α to help better grip bone and/or calcified cartilage. In someembodiments including a plurality of the bone-engaging elements 74, thebone-engaging elements 74 can cover a distal end surface of the elongatebody 72 such that the bone-engaging elements 74, e.g., a plurality ofteeth, can form a textured bone-engaging surface.

Although the bone-engaging elements 74 are shown integrally formed withthe elongate body 72, any one or more of the bone-engaging elements 74can be movably coupled to the elongate body 72. For non-limitingexample, the bone-engaging elements 74 can be retractable such that inan extended position the bone-engaging elements 74 can extend distallybeyond the guide's distal end 70 a and in a retracted position can becontained within the elongate body 72. Retraction and extension ofmovable bone-engaging elements can be controlled in any way, as will beappreciate by a person skilled in the art, such as through actuation ofa control mechanism, e.g., a knob, a button, a lever, an electronicsignal communicator, etc., at the proximal end 70 b of the guide 70. Insome embodiments, the bone-engaging elements 74 can be removably coupledto the guide 70.

As mentioned above, the guide 70 can be configured to be removablycoupled to the shaft 12 with the shaft's elongate body 18 slidablyreceivable within the inner passageway 76 of the guide 70. The guide'spassageway 76 can thus, as shown in this embodiment, be substantiallycylindrical-shaped to match the shape of the shaft 12. The correspondingcylindrical shapes of the guide's passageway 76 and the shaft's elongatebody 18 can allow the shaft 12 to be both linearly and rotatably movablewithin the inner passageway 76, which can help position the guide 70relative to the shaft 12 and to the scaffold 10 attached to the prongs20 of the shaft 12. The diameter D1 of the shaft's elongate body 18 canthus be less than a diameter D8 of the guide's passageway 76 to allowthe elongate body 18 to be movable therein. The diameter D8 can have anysize, e.g., about 0.305 in. (7.7 mm). The elongate body 72 can also haveany shape, e.g., cylindrical, etc., and have any diameter D9, e.g.,about 0.375 in. (9.5 mm). The elongate body's diameter D9 can beconstant along the longitudinal length L9 of the guide 70, or thediameter D9 can vary with, e.g., the elongate body 72 having a differentdiameter D9 in at least a portion of the distal end 70 a.

The elongate body 72 can also include one or more windows or cut-outs 78adjacent the distal end 70 a. One or more windows at the guide's distalend 70 a are optional, and they can be configured to enable viewing ofat least one surgical instrument and/or a surgical site within theguide's passageway 76 at least at the distal end 70 a. The cut-outs 78can have any configuration. As illustrated in this embodiment, thecut-outs 78 can include one or more holes or openings formed in asidewall of the elongate body 72 of the guide 70 such that the cut-outs78 are in communication with the guide's passageway 76. Although fourcut-outs 78 are shown, the guide 70 can include any number of cut-outs78. Moreover, each of the cut-outs 78 can be the same or different fromany other of the cut-outs 78. The cut-outs 78 are illustrated asrectangular shapes having a length 781 of about 0.375 in. (9.5 mm) and awidth 78 w, e.g., about 0.18 in. (4.8 mm), but the cut-outs 78 can haveany size and shape. The cut-outs 78 can be arranged at the guide'sdistal end 70 a in any configuration, such as equidistantly spacedradially around a central longitudinal axis A3 of the guide 70, e.g.,about 90° apart as illustrated. The windows 78 can be located anylongitudinal distance 78 d from a distal-most end of the guide 70, e.g.,about 0.05 in. (1.3 mm), to allow for viewing of components within thepassageway 76 in the distal end 70 a of the guide 70.

In an alternate embodiment of a delivery guide 70′, illustrated in FIG.24, the guide 70′ can be configured similar to the guide 70 except thata window formed adjacent a distal end 70 a′ can be in the form of atransparent portion 72 t of an elongate body 72′ of the guide 70′. Thetransparent portion 72 t can be configured to allow visualizationthrough the guide 70′ while helping to keep tissue, fluid, and any othermaterial from passing into an inner lumen 76′ of the guide 70′ through aside of the elongate body 72′. Although the transparent portion 72 t isillustrated only at a distal end of the elongate body 72′, thetransparent portion 72 t can extend along any full or partial length ofthe elongate body 72′. The distal transparent portion 72 t can be acontinuous transparent portion, e.g., a transparent cylindrical body asshown, although as will be appreciated by a person skilled in the art,the distal transparent portion can includes a plurality of transparentwindows formed in and arranged around the elongate body 72′ similar tothe cut-outs 78. A person skilled in the art will also appreciate thatthe term “transparent” as used herein is intended to include anycombination of one or more see-through materials including opticallyclear material and translucent material.

As mentioned above, instead of bone-engaging elements being integrallyformed with a delivery guide, the bone-engaging elements can beremovably coupled to the guide. The alternate guide 70′ illustrates oneembodiment of one or more bone-engaging elements 74′ extending distallyfrom a distal ring 71 that is configured to be removably coupled to theguide's distal end 70 a′ in any way appreciated by a person skilled inthe art, e.g., threadably attached, snap fit, etc. In this way, distalrings having different sizes and shapes and/or having different numbers,sizes, shapes, etc. of bone-engaging elements can be coupled to adelivery guide to allow the delivery guide to better accommodatedifferently sized and shaped tissue defect sites and differently sizedand shaped tissue scaffolds. Modular distal rings can optionally besupplied with a delivery guide as part of a kit.

In another alternate embodiment of a delivery guide 70″, illustrated inFIG. 25, the guide 70″ can be configured similar to the guide 70 or theguide 70′ except that the guide 70″ can include at least one alignmentmechanism configured to position a tool, e.g., a delivery shaft, a punchtool, a fastener-applying tool, etc., inserted through an inner lumen orpassageway 76″ extending between a distal end (not shown) and a proximalend 70 b″ of the guide 70″ in a predetermined radial position relativeto the guide 70″. In this way, a position of the tool at the surgicalsite can be known even if it is difficult or impossible to view the toolat the surgical site, such as can often be the case in a mini-opensurgical procedure. The optional alignment mechanism can have a varietyof sizes, shapes, and configurations. For non-limiting example, thealignment mechanism can include an alignment guide label printed,embossed, or otherwise viewable on the guide 70″ that indicates a properradial positioning of a surgical tool inserted into the passageway 76″.The surgical tool can have a corresponding alignment guide label suchthat matching alignment guide labels can be aligned to help ensureproper positioning of the tool within the guide 70″. In the illustratedembodiment, the alignment mechanism includes at least one elongate slot80 formed in at least the proximal end 70 b″ of the guide 70″. Asurgical tool inserted through the proximal end 70 b″ of the guide 70″can have one or more corresponding alignment mechanisms, e.g., pins,protrusions, elongate tracks, etc., configured to be received in andslide through the slots 80 to orient the tool in a particular radialposition such that its position at the distal end of the guide 70″ canbe known even without visual confirmation.

Regardless of the type of delivery guide introduced into a body of apatient to help remove the scaffold 10 from the prongs 20 of thedelivery shaft 12, the delivery guide can be introduced into thepatient's body over the shaft 12. In one embodiment illustrated in FIGS.26 and 27, with the shaft 12 disposed through the opening 62 in thetissue 64, the delivery guide 70 can be advanced distal end 70 a firstover the shaft 12 such that the shaft 12 can be slidably received in theguide's passageway 76. At any time prior to contact of the guide'sdistal end 70 a with the scaffold 10 attached to the prongs 20, thescaffold 10 can be positioned above and aligned with the cavity 66, asillustrated in FIG. 26, such that distally advancing the scaffold 10 canposition the scaffold 10 within the cavity 66, as shown in FIG. 27. Theprongs 20 can be positioned to contact at least a surface of a bone 67at a bottom surface of the cavity 66, thereby positioning the scaffold10 with respect to the cavity 66 and providing stability to the shaft 12as the guide 70 is advanced over the elongate body 18 of the shaft 12.As mentioned above, the prongs 20 can be distally tapered, which canhelp the prongs 12 grip and/or penetrate the bone 67. Additionally, thebone 67 can additionally or alternatively include calcified cartilage.

The delivery guide 70 can be distally advanced over the shaft 12, asshown by the directional arrow in FIG. 26, with the guide's distal end70 a eventually contacting the scaffold 10 on the prongs 20. Because theguide 70 can be configured to surround the shaft 12, the distal end 70 aof the guide 70 can distally advance over shaft 12 and hence over theprongs 20 extending therefrom and contact the scaffold 10 withoutcontacting the prongs 20. The delivery guide 70 can be distally advancedthrough the tissue 64 until the distal end 70 a of the guide 70 pushesthe scaffold 10 toward and into the cavity 66, which can optionally alsomove the scaffold 10 from the folded configuration to the planarconfiguration. The bone-penetrating elements 74 can penetrate throughthe scaffold 10 and contact at least a surface of the bone 67, which canhelp hold the delivery guide 70 in position in the patient andtemporarily hold the scaffold 10 in a fixed position in the cavity 66. Aperson skilled in the art will appreciate that one or more of thebone-penetrating elements 74 can be configured to not penetrate throughthe scaffold 10 and hence not contact the bone 67. With the guide 70holding the scaffold 10 in a desirable position in the cavity 66, theshaft 12 can be removed from the guide 70 and from the patient's body.The shaft 12 can be removed in any way, such as manipulating theproximal end 12 b of the shaft 12 proximally extending beyond theguide's proximal end 70 b, as shown in FIG. 27, and proximally pullingthe shaft 12. Movement of the guide 70 against the scaffold 10 can pushthe scaffold 10 off one or more of the prongs 20, but if any of theprongs 20 extend through the scaffold 10 after the guide 70 holds thescaffold 10 in the cavity 66, proximal movement of the shaft 12 throughthe guide's passageway 76 can pull the prongs 20 out of the scaffold 10.

Optionally, with the scaffold 10 in an implantation position within thecavity 66, the scaffold 10 can be attached to the patient. A personskilled in the art will appreciate that the scaffold 10 in theimplantation position can fit entirely within the cavity 66 or that aportion of the scaffold 10 can extend outside the cavity 66 if, e.g.,the scaffold 10 was cut to a size larger than the cavity 66. Thescaffold 10 can be attached to the patient in any way, as will beappreciated by a person skilled in the art. In some embodiments, theguide 70 can be removed from the patient after the guide 70 advances thescaffold 10 into the implantation position, but in an exemplaryembodiment, the guide 70 remains in place while at least one surgicaltool is advanced through the guide's passageway 76 to affix the scaffold10 to the patient.

Any one or more surgical tools can be used to affix the scaffold 10 inany way. In one embodiment, illustrated in FIGS. 28-31, a bonepreparation tool such as a punch tool 82 can be used to punch at leastone hole or opening 86 in the scaffold 10 and in the bone 87 underlyingthe scaffold 10, and a scaffold seating tool such as a fastener-applyingtool 88 can be used to apply at least one securing mechanism or fastener90 through the one or more openings 86 created by the punch tool 82 tofasten the scaffold to the bone 87. In some embodiments, a single toolcan be configured as a bone preparation tool and a scaffold seatingtool, e.g., a staple inserter device such as those discussed in moredetail in previously mentioned U.S. Pat. No. 6,447,517 issued Sep. 10,2002 titled “Instrument For Inserting Graft Fixation Device,” U.S. Pat.No. 6,179,840 issued Jan. 30, 2001 titled “Graft Fixation Device AndMethod,” and U.S. Pat. No. 6,423,073 issued Jul. 23, 2002 titled,“Instrument For Inserting Graft Fixation Device.” The punch tool 82 andthe fastener-applying tool 88 can each be separately advanced throughthe delivery guide 70 holding the scaffold 10 in the cavity 66, therebyallowing the punch tool 82 and the fastener-applying tool 88 to be moreaccurately positioned relative to the scaffold 10 and help assure thatthe one or more fasteners 90 applied by the fastener-applying tool 88are positioned at a desirable location with respect to the scaffold 10and that the one or more fasteners 90 properly align with the formed oneor more openings 86. A person skilled in the art will appreciate thatother bone preparation tools and scaffold seating tools can be used, ifone or either is used at all in applying the scaffold 10. Fornon-limiting example, a fastener can come from the bone 87 and thenthrough the scaffold 10.

The punch tool 82 can have a variety of sizes, shapes, andconfigurations. Generally, the punch tool 82 can include any punch toolconfigured to create one or more openings or holes in a tissue scaffoldand in bone, as will be appreciated by a person skilled in the art.Non-limiting embodiments of punch tools can be found in U.S. Pat. No.6,447,517 issued Sep. 10, 2002 titled “Instrument For Inserting GraftFixation Device,” U.S. Pat. No. 6,179,840 issued Jan. 30, 2001 titled“Graft Fixation Device And Method,” and U.S. Pat. No. 6,423,073 issuedJul. 23, 2002 titled, “Instrument For Inserting Graft Fixation Device,”which are hereby incorporated by reference in their entireties. In oneembodiment illustrated in FIG. 28, the punch tool 82 can include anelongate body 83 having at least one bone-penetrating element 85 at adistal end 82 a of the punch tool 82. The punch tool 82 can have anylongitudinal length, but in an exemplary embodiment the punch tool 82can be longer than the delivery guide 70 to allow the punch tool 82 tobe disposed in the passageway 16 and proximally extend beyond theguide's proximal end 70 b when distal ends 70 a, 82 a of the guide 70and the punch tool 82 are each contacting the scaffold 10 inside thepatient. The bone-penetrating elements 85 can have any size, shape, andconfiguration. The bone-penetrating elements 85 can generally beconfigured as teeth or prongs, similar to the bone-engaging elements 74discussed above, that are configured to at least partially penetrateinto bone to help form a hole or opening in bone. The bone-penetratingelements 85 of the punch tool 82 can be different, e.g., sharper and/orlonger, than the bone-engaging elements 74 of the guide 70 to allow thebone-penetrating elements 85 of the punch tool 82 to form appropriateholes in bone to receive fasteners. As illustrated, the bone-penetratingelements 85 of the punch tool 82 can be cylindrical, rigid, solidmembers.

As mentioned above, the punch tool 82 can be configured to be removablycoupled to the guide 70 with the punch tool's elongate body 83 slidablyreceived within the inner passageway 76 of the guide 70. The punchtool's elongate body 83 can thus, as shown in this embodiment, besubstantially cylindrical-shaped to match the shape of the innerpassageway 76. The corresponding cylindrical shapes of the guide'spassageway 76 and the punch tool's elongate body 83 can allow the punchtool 82 to be both linearly and rotatably movable within the innerpassageway 76, unless an alignment mechanism, e.g., one or more pins 87,is present to prevent rotational motion of the punch tool 82 within thepassageway 76 of the guide 70. The punch tool's elongate body 83 canthus have a diameter D10 less than the diameter D8 of the guide's innerpassageway 76 to allow the elongate body 83 to be movable therein.Conversely, the punch tool's proximal end 82 b can have a diameter D11that is greater than the diameter D8 of the guide's passageway 76 andgreater than the elongate body's diameter D10. In this way, the punchtool's proximal end 82 b can serve as a stop mechanism configured tolimit a distance that the punch tool 82 extends into the guide 70 andthus into bone.

Although the punch tool 82 can be a solid member as shown, the punchtool 82 can include one or more passageways formed therethrough. Fornon-limiting example, the punch tool 82 can include a tunnel extendingthrough its distal and proximal ends 82 a, 82 b that is configured toreceive at least one surgical instrument disposed therethrough, e.g., avacuum device configured to suction fluid, tissue, etc. away from asurgical site.

In use, as illustrated in FIG. 29, the punch tool 82 can be distallyadvanced into the delivery guide 70 and through the opening 62 in thetissue 64 until a distal end (not shown) of the punch tool 82 contactsthe scaffold 10 or is otherwise desirably positioned with respect to thescaffold. Proper positioning of the punch tool 82 inside the guide 70can be verified by feel and/or by visualization through the cut-outs 78in the guide 70. If the punch tool 82 and the guide 70 include analignment mechanism, the alignment mechanism can align the punch tool 82with respect to the guide 70 before and/or after the punch tool isadvanced therethrough to predictably align the punch tool's distal endwith respect to the scaffold 10 and thus also predictably position theopenings 86 formed by the punch tool 82. The alignment mechanism canalso align the bone-penetrating elements 85 of the punch tool 82 at apredetermined radial position relative to the guide 70. Generally, withthe punch tool 82 disposed in the guide's passageway 76, the punch tool82 can be distally advanced, e.g., by hitting the proximal end 82 b ofthe punch tool 82 with a hammer 84 one or more times, to create the oneor more openings 86 in the scaffold 10 and in the bone 87 underlying thescaffold 10. The punch tool 82 is optionally used, but because the bone87 can be very hard, forming one or more openings 86 through thescaffold 10 and into the bone 87 can ease application of the one or morefasteners 90. Any time after the punch tool 82 has formed the openings86 as desired, the punch tool 82 can be removed from the patient, e.g.,by proximally moving the punch tool 82 through and out of the guide 70.Distal pressure can be applied to the guide 70 as the punch tool 82 isremoved, thereby holding the scaffold 10 in place.

As shown in one embodiment in FIG. 30, after the punch tool 82 isremoved from the guide 70, the fastener-applying tool 88 can be distallyadvanced into the delivery guide 70 and through the opening 62 in thetissue 64 similar to the punch tool 82. Proper positioning of thefastener-applying tool 88 inside the guide 70 can also be similarlyverified by feel and/or by visualization through the cut-outs 78 in theguide 70. If present, an alignment mechanism can also be similarly usedto align the fastener-applying tool 88 with respect to the guide 70 andthe scaffold 10. The punch tool 82 and the fastener-applying tool 88 canbe similarly configured with alignment mechanisms such that the punchtool 82 and the fastener-applying tool 88 are similarly radiallyoriented within the guide 70 at predetermined positions such that legsof a fastener 90 applied by the fastener-applying tool 88 can extendinto holes 86 created by the punch tool 82. The alignment mechanism canthus help ensure that the fastener-applying tool 88 is positioned toapply the one or more fasteners 90 through the holes 86 formed by thepunch tool 82, e.g., without requiring the position of thefastener-applying tool 88 in the patient to be visually or otherwiseverified. The fastener-applying tool 88 can be actuated to apply one ormore fasteners in any way. The fastener-applying tool 88 can include anyfastener-applying tool configured to apply one or more fasteners to atissue scaffold, as will be appreciated by a person skilled in the art.Generally, the fastener-applying tool 88 can have at last onefastener-retaining member on a distal end of the fastener-applying tool88 and be configured to retain at least one fastener with thefastener-retaining member and to apply at least one fastener through thescaffold 10 to the bone 87 underlying the scaffold 10. Non-limitingembodiments of fastener-applying tools can be found in previouslymentioned U.S. Pat. No. 6,447,517 issued Sep. 10, 2002 titled“Instrument For Inserting Graft Fixation Device,” U.S. Pat. No.6,179,840 issued Jan. 30, 2001 titled “Graft Fixation Device AndMethod,” and U.S. Pat. No. 6,423,073 issued Jul. 23, 2002 titled,“Instrument For Inserting Graft Fixation Device.” After one or morefasteners 90 are applied to attach the scaffold 10 to the bone 87, thefastener-applying tool 88 and the guide 70 can be removed from the bodyof the patient, e.g., by proximally moving the fastener-applying tool 88and the guide 70 together or separately through and out of the opening62 in the tissue 64.

Although only one X-shaped fastener 90 is shown in FIG. 31 attaching thescaffold 10 to the patient, any number of fasteners 90 can be used toaffix the scaffold 10 within the cavity 66. A person skilled in the artwill appreciate that although the fasteners 90 are illustrated asstaples, the one or more fasteners used to attach the scaffold 10 to thepatient can include one or more types of fasteners, e.g., a staple,tissue tack, suture, adhesive, etc., in any combination. The deliveryguide 70 can be repositioned one or more times with respect to thescaffold 10 to facilitate punching one or more additional holes in thescaffold 10 using a punch tool advanced through the guide 70 and tofacilitate application of one or more additional fasteners through theone or more additional holes using a fastener-applying tool advancedthrough the guide 70.

The devices discussed herein can be made from any combination of rigidand/or flexible materials, but in an exemplary embodiment the materialsare biocompatible. A person skilled in the art will appreciate that theterms “flexible” and “rigid” as used herein are intended to encompass avariety of configurations. Generally, a “flexible” member has somedegree of elasticity, e.g., is capable of bending without breaking,while a “rigid” member lacks elasticity. In an exemplary embodiment, thedevices or at least portions thereof are composed of at least onebiocompatible material, e.g., plastic, titanium, stainless steel, etc.

A person skilled in the art will appreciate that the present inventionhas application in conventional endoscopic and open surgicalinstrumentation as well application in robotic-assisted surgery.

The devices disclosed herein can also be designed to be disposed ofafter a single use, or they can be designed to be used multiple times.In either case, however, the device can be reconditioned for reuse afterat least one use. Reconditioning can include any combination of thesteps of disassembly of the device, followed by cleaning or replacementof particular pieces and subsequent reassembly. In particular, thedevice can be disassembled, and any number of the particular pieces orparts of the device can be selectively replaced or removed in anycombination. Upon cleaning and/or replacement of particular parts, thedevice can be reassembled for subsequent use either at a reconditioningfacility, or by a surgical team immediately prior to a surgicalprocedure. Those skilled in the art will appreciate that reconditioningof a device can utilize a variety of techniques for disassembly,cleaning/replacement, and reassembly. Use of such techniques, and theresulting reconditioned device, are all within the scope of the presentapplication.

One skilled in the art will appreciate further features and advantagesof the invention based on the above-described embodiments. Accordingly,the invention is not to be limited by what has been particularly shownand described, except as indicated by the appended claims. Allpublications and references cited herein are expressly incorporatedherein by reference in their entirety.

One skilled in the art will appreciate further features and advantagesof the invention based on the above-described embodiments. Accordingly,the invention is not to be limited by what has been particularly shownand described, except as indicated by the appended claims. Allpublications and references cited herein are expressly incorporatedherein by reference in their entirety.

What is claimed is:
 1. A tissue scaffold delivery system, comprising: adelivery guide having an inner lumen extending therethrough and at leastone tooth extending from a perimeter of a distal end thereof at a fixedlongitudinal position relative to the delivery guide, the at least onetooth being configured to penetrate a tissue scaffold and to engage boneto hold a tissue scaffold in a fixed position relative to the bone, thedelivery guide further including at least one window adjacent to thedistal end and configured to enable viewing of a component disposedwithin the inner lumen at the distal end.
 2. The system of claim 1,wherein the at least one window comprises a plurality of cut-outs formedin the delivery guide.
 3. The system of claim 1, wherein the at leastone window comprises a transparent portion formed in the delivery guide.4. The system of claim 1, further comprising a bone preparation toolconfigured to be advanced through the inner lumen of the delivery guideand to prepare bone for attachment of a tissue scaffold thereto.
 5. Thesystem of claim 4, wherein the bone preparation tool comprises a punchtool having at least one prong configured to punch at least one holethrough a tissue scaffold held by the at least one prong and into boneunderlying the tissue scaffold.
 6. The system of claim 1, furthercomprising a scaffold seating tool configured to be advanced through theinner lumen of the delivery guide and to seat a tissue scaffold held inposition by the at least one tooth.
 7. The system of claim 6, whereinthe scaffold seating tool comprises a fastener-applying tool having afastener-retaining member on a distal end thereof and configured toretain at least one fastener and to apply the fastener through a tissuescaffold held in position by the at least one tooth to fasten the tissuescaffold to a bone underlying the tissue scaffold.
 8. The system ofclaim 1, further comprising a delivery shaft having at least one prongextending from a distal end thereof, the at least one prong beingconfigured to extend through a tissue scaffold, and the delivery guidebeing disposable over the delivery shaft such that the at least onetooth is configured to engage a tissue scaffold disposed on the at leastone prong of the delivery shaft.
 9. The system of claim 8, furthercomprising a delivery cannula having a funnel coupled to a distal endthereof, the delivery shaft being slidably disposable through thedelivery cannula.
 10. The system of claim 1, wherein the delivery guideincludes an alignment mechanism configured to position a tool insertedtherethrough in a predetermined radial position relative to the deliveryguide.
 11. The system of claim 1, further comprising a loading blockhaving a surface configured to seat a tissue scaffold thereon, thesurface having at least one opening formed therein and configured toreceive the at least one tooth on the delivery guide such that the atleast one tooth can extend through a tissue scaffold seated on thesurface, the loading block further including a guide member extendingfrom the surface and having at least one channel formed therein, the atleast one channel being positioned to guide the at least one tooth intothe at least one opening on the surface.
 12. The system of claim 11,wherein the at least one tooth comprises two teeth, the at least oneopening comprises two openings, and the at least one channel comprisestwo channels.
 13. The system of claim 11, wherein the at least oneopening formed in the surface of the loading block is in the form of anelongate slot configured to allow the at least one tooth on the deliveryguide to slide therein.
 14. The system of claim 11, wherein the at leastone opening is located a predetermined distance from a terminal edge ofthe surface such that the at least one tooth will extend through apredetermined location on a tissue scaffold seated on the surface andhaving perimeter abutting the terminal edge.
 15. A tissue scaffolddelivery system, comprising: a delivery guide having an inner lumenextending therethrough and at least one tooth extending from a perimeterof a distal end thereof, the at least one tooth being configured topenetrate a tissue scaffold and to engage bone to hold a tissue scaffoldin a fixed position relative to the bone, the delivery guide furtherincluding at least one window adjacent to the distal end and configuredto enable viewing of a component disposed within the inner lumen at thedistal end; and a loading block having a surface configured to seat atissue scaffold thereon, the surface having at least one opening formedtherein and configured to receive the at least one tooth on the deliveryguide such that the at least one tooth can extend through a tissuescaffold seated on the surface, the loading block further including aguide member extending from the surface and having at least one channelformed therein, the at least one channel being positioned to guide theat least one tooth into the at least one opening on the surface.
 16. Thesystem of claim 15, wherein the at least one tooth comprises two teeth,the at least one opening comprises two openings, and the at least onechannel comprises two channels.
 17. The system of claim 15, wherein theat least one opening formed in the surface of the loading block is inthe form of an elongate slot configured to allow the at least one toothon the delivery guide to slide therein.
 18. The system of claim 15,wherein the at least one opening is located a predetermined distancefrom a terminal edge of the surface such that the at least one toothwill extend through a predetermined location on a tissue scaffold seatedon the surface and having perimeter abutting the terminal edge.
 19. Atissue scaffold delivery system, comprising: a delivery guide having aninner lumen extending therethrough and at least one tooth extending froma perimeter of a distal end thereof, the at least one tooth beingconfigured to penetrate a tissue scaffold and to engage bone to hold atissue scaffold in a fixed position relative to the bone, the deliveryguide further including at least one window adjacent to the distal endand configured to enable viewing of a component disposed within theinner lumen at the distal end; a delivery shaft having at least oneprong extending from a distal end thereof, the at least one prong beingconfigured to extend through a tissue scaffold, and the delivery guidebeing disposable over the delivery shaft such that the at least onetooth is configured to engage a tissue scaffold disposed on the at leastone prong of the delivery shaft; and a delivery cannula having a funnelcoupled to a distal end thereof, the delivery shaft being slidablydisposable through the delivery cannula.
 20. The system of claim 19,wherein the at least one tooth extends from the perimeter so as to beoutside a pathway of the inner lumen of the delivery guide.